how to remote control your telescope - part 1

it's a wonderful night out but it's butt-freezing cold - what can i do ?

With the weather being as cold and bad as it is right now, i spent some time researching ways to remotely control the telescope without having to leave the comfortable warmth of the house. I would like to be able to do the following:

• Remote control the telescope through a planetarium software on a laptop
• Remote control my DSLR to take pictures
• Remote control a webcam to take planetary images or to track what the scope is looking at when a DSLR camera is used

So far i understand that the following pieces are necessary:

1. A windows laptop
   
2. Planetarium software and necessary drivers that will let you control a telescope
3. An approximately x meter long serial cable to connect the telescope to a laptop
   
4. A webcam that can work in low light conditions and a piece of software that displays what the webcam is seing. I need this webcam since my DSLR does not allow for direct output of finder video data. If it could do that, then i would not need the webcam and could use the DSLR's output directly
5. An optional finderscope that i can attach the webcam to in order to use it for tracking or guiding
6. A guiding software that works with a webcam
   
7. An active USB repeater of x meter length to get the webcam signal to the laptop
8. A remote release cable or wireless remote release solution of x meter length for my SLR camera

So far these are the components i've been able to find with great help from the community on www.cloudynights.com. Now to the details:

Windows laptop and the necessary planetarium software
My research showed that there are a couple of nice planetarium applications out there. Not all of them include telescope control features. Some that do offer this are free (Stellarium) and some have to be paid for (Starry Night Pro). I decided to look at Stellarium since it is free. I am using Starry Night Digital Download on my Mac and updating to the Pro version, which would allow for telescope control was over 100USD.

The reason for going with a windows based laptop and not with a macbook was, that it appears that the ASCOM driver plattform as well as the Celestron Nexstar driver are not available for OS X.

So these are the components that i found out you need:

• Planetarium Software: Stellarium Software (v.10.2) / Free
• Interface to control the Scope via Stellarium: Stellariumscope / Free
• Driver Plattform: ASCOMPlatform5b / Free
• Driver for the Celestron Nexstar6SE: Celestron (5.0.14) / Free
• Webcam: Celestron Neximage / found it on ebay for 99USD
• Finderscope: Antares 5x70 finderscope with mounting bracket. This finder allows you to change eyepieces so that an optional webcam can be attached / 130USD
• Remote control cable or wireless extension for my Panasonic G1 DSLR: still looking : ( / 38USD on ebay, chinese made)
• Serial cable extension: available almost everywhere. No active components are necessary / approx. 10 USD
• Active USB cable: available almost everywhere. I bought a 5 meter cable and the instructions on the box say that four of those cables can be strung together/ approx. 20 USD

You can also find most of the above files in my public folder on me.com. Here's the link: http://public.me.com/baierfamily - the password is "nexstar"

I've received some comments why i did not use the Celestron Nexremote software. That's a good question ! I have no idea where i put the disc when i unpacked the scope ! And from what i could read in the manual, the Nexremote software only seems to emulate the hand controller. You still need a separate planetarium software integration. So until i find the disc up in the attic, i'll have to use the tools i currently have : )

Addition (Jan 15th 2010): I got a nice comment from a cloudynights member called "kkokkolis" (i think he's from Greece) and he pointed out that the nexremote software adds some nice features like:

• Text to speech
• Extended balloon search
• A virtual port to use nexremote parallel to other software like Stellarium

Thanks Kkokkolis for the input - i'll have to try Nexremote the next time i get a chance !

This is how i installed and set up everything:

1. Install Stellarium
2. Install Stellariumscope
3. Install ASCOM Driver Platform
4. Install Celestron Driver
5. Start Stellariumscope and chose the Nexstar 6SE from the list of telescopes. Then hit the "connect" button
6. Start Stellarium
7. Now you get a nice little window with left, right, up and down arrow and when you click on those, then - holy cow - the telescope moves ! I was already quite impressed by then !
8. Align your telescope. (so far, that's as far as i got because the weather has been so bad, i've not been able to align the telescope yet)
   

I ordered a 7.5 meter serial cable extension for the standard celestron serial cable which worked flawlessly. I also ordered the neximage webcam on ebay for approx. 100USD. I read online that the necessary USB extensions are quite a different matter and that for anything going above 5 meters a special "active" USB "repeater" cable has to be used. So i ordered a 5 meter active extension at a local store.

Now i'm waiting for a good night to align the telescope so that i can see if the point and goto functionality within Stellarium works as designed and i'll have to wait for the neximage webcam as well.

Then i'll have to figure out how to autoguide using the webcam and from what i've seen this seems to be a quite complicated task that'll take me a while to wrap my head around. And it also looks like i'll need yet another off axis guidescope ? Nooooooooo !

photography setup

Lots of pieces you don't want to drop in the dark...

Due to popular request i took some pictures of how exactly the camera attaches to the telescope. I currently am using the following setups:

1. Prime Focus method
2. Eyepiece projection method

Prime focus setup

For this setup i am using the following pieces: a 1.25" adapter that you insert into the "base" of the telescope where usually the diagonal prism would go.(You can use a diagonal prism as well, if you don't want your camera-adapter-rig to point parallel to the telescope, but up at a 90 degree angle). Next comes a T-Ring that screws onto the 1.25" adapter and then i am using an adapter that goes from M42 to Micro 4/3rds, because the T-Ring that i have has the M42 size/dimension and my panasonic is a "Micro 4/3rds" camera. You can get all kinds of T-rings to fit your type of camera. I got mine at www.cncsupplyinc.com. Here's a picture of all the pieces.

So there you have the visual back that usually is attached to the telescope on the very left, then comes the 1.25" adapter with the T-ring already screwed on and then comes the adapter that goes onto the camera.

Eyepiece projection method

This is basically the same setup but you add an additional tube that holds your eyepiece of joice. This tube goes between the camera adapter and the T-ring. The eyepiece is held in place by the little silver screw you can see at the bottom of the image, right in the middle of the tube. Here's a picture how that looks:

This setup gets quite long and if you attach this to the 6SE then you won't be able to point your telescope straight up. Please make sure you set the slew limits correctly. When i first used this setup on my scope i had to hastily turn the power off when i saw that the camera was about the hit the base of the telescope - which probably would have broken or at least bent the whole setup badly...

Here's a picture of all the pieces screwed onto the 6SE:

here's another angle:

So if you want to be able to look straight up, you should use a diagonal prism. I also found that it makes sense to screw the whole assembly together inside in the light and not to take everything outside in pieces. ...I did that the first time and ended up dropping the T-Ring in the grass and it took me 10 minutes to find it again....

So there you have it - it took me some time to find out which pieces are necessary to use your digital SLR for astrophotography. I'm still having a very hard time focusing and deep sky objects don't show up in my viewfinder at all. AND my viewfinder is so bright i'm almost blinded when i try to use it in the dark. But i guess i'll figure all these things out in due time....

first Moon photo

A full moon can be so bright !

Last night i went out to try to take a picture of the full moon using the prime focus method. I quickly realized that the full moon does not fit into the viewfield so i had to take two pictures which i then had to doctor together in photoshop. I wanted to try the "photomerge" feature but ever since i upgraded to Snow Leopoard, Photoshop crashes alot and the photomerge feature is not working at all anymore......

So here is my first picture of the moon:

The image was altered in photoshop using unsharpen mask as well as brightness and contrast correction.

It was a cloudy night and i think a little cloud can be seen at the very top of the image. I probably took 10 to 15 pictures but could only use two or three in the end due to clouds that only showed up in the final images and where not visible on the cameras LCD screen.

first astrophoto !

A light polluted harbour town

I decided to take the telescope with us on our vacation to the south of france - to a place called "Grau du Roi" in the vicinity of Montpellier. I was hoping for dark skies and alot of free time to spend taking photos.

I did get the following gear in order to be able to take pictures through the scope:

- Eyepiece and prime focus projection adapter from CNCSupply Inc. This set can be used to take photos by directly attaching the camera to the telescope or by placing an eyepiece between the camera and the telescope. Here's a picture of the setup for eyepiece projection:

From right to left: 1.25" adapter, Projection Body, T-Ring and T42 to micro 4/3rds adapter (purchased separately on ebay for 40USD) that is necessary to attach my Panasonic G1 camera. So basically all these pieces get screwed together and the left part goes into the telescope and the right part screws onto the digital camera.

Unfortunately, although our apartment was situated right at the beachfront, the light pollution from cities close by was quite bad. Especially the nearby harbour seemed to have huge lights pointing up at the sky.

Man, focusing can be hard !

But i gave it a try anyway and took a couple of shots of Jupiter with the moons Callisto, Europa and (i think) Ganymede. I had a really hard time getting a good focus. My Panasonic G1 has an option where you can zoom into the image to check the focusing but this mode only works for a couple of seconds and it was really hard to manually focus using the focus knob on the telescope. Here's the original photo set after aligning and stacking:

I was quite disappointed that Jupiters moons where not visible at all in the images after they stood out so well when looking through the telescope. Maybe i will have to try longer exposure times next time around...

And here's the same image after adjusting the brightness and contrast settings in photoshop:

I took 6 images and stacked them using "Keiths image stacker" and then increased the contrast using Photoshop CS4. I did not try the prime focus method and was unable to use my other 40mm eyepiece since it was to wide to fit into the projection body.

So far i like the projection adapter but what i would really like is a way to somehow use the lense of my digital camera in order to zoom into an image. So far i've not found any adapters that would allow me to do this.

the second night out

telescope alignment
After my so-so experience the night before I spent some time surfing the net looking for alignment issues regarding the Nexstar SE line of telescopes. Here is what I found on the net and also what i found out later by trial and error:

1. make absolutely sure that your tripod is level
2. adjust the "anti-blacklash" settings of your telescope to ensure better GOTO performance. I'll try to go into the details further down the page
   
3. to get better results, use the two star alignment or three star alignment feature instead of the SkyAlign feature
4. if you are only looking at a certain part of the sky, use the sync command to re-sync the telescope at a certain object of interest

anti-backlash
I found is a very good description about what this is and how it can be corrected on the the great nexstarsite. Basically it says that you're supposed to do the following:

1. point your scope at a distant object. This can be done during the day.
   
2. set the slew rate to 4 or 5 using the RATE button on the hand controller
3. press one of the directional buttons and observe if the object starts to immediately move or if it takes a while to move
4. the longer it takes the image to move, the more likely you have to put a higher value into the "anti backlash" settings (Azm Backlash corresponds to the left/right buttons, Alt Backlash corresponds to the up/down buttons)

So I went and moved the telescope around a bit in the Azm and Alt axis and then put in values of 20 for Azm positive/negative and 40 for the alt positive/negative. I set both positive and negative values to the same number because on the nexstar site it said: "Normally the positive and negative values on either axis should be set the same."

Why did I set it to 20 and 40 ? Well, I had no idea what those values actually meant, I only knew they go from 0 to (I think) 99. So I just guestimated and set two different values in order to see how those values would affect the movement of the scope.

The results were that the scope started to almost immediately react to left/right commands but made a huge jump up or down whenever I pushed the Alt (up/down) buttons. So obviously the setting of 40 was to high.

After about 15 minutes of trial and error i ended up with the following values:

• Azm Backlash positive: 25 / Azm Backlash negative: 25
• Alt Backlash positive: 15 / Alt Backlash negative: 15
  

These values will most likely be different for you since not all telescopes experience the same amount of backlash.

Personally I think that the quality of the product should be good enough to not require any additional corrections by the user - but that's probably just the mac user in me speaking his mind....

Important addition: when you attach different gear on your telescope, then the values that you entered will most likely not work as well anymore. I just got back after attaching my digital camera and noticed that due to the added weight my ALT anti-backlash settings of 15/15 made the image "jump" again. I had to set it to a value of 4/4 in order to minimize the backlash. So i guess the more weight you add, the lower the ALT number ? I'll have to give it some more tries...

Addition 09 January 2010: While i was aligning my new finderscope i changed the backlash settings again. I now have got a setting of 10 for the alt negative and positive and a setting of 50 for the azm negative and positive. I changed the values because i felt like there still was alot of pause in the azimutz axis.

...and out on the garage I went again
This time around i made absolutely sure that the tripod was as level as I could get it with the limited tools (small bubble level) I had. I wonder if there are any other more sophisticated levels out there.

I then used the two star auto align by choosing Arcturus and then Altair as the guide stars. Got the "alignment confirmed" message - so far so good.

I then chose Jupiter from the Planets menu and watched the scope slew all the way over to jupiter. While it was moving, I looked through the finderscope and when the scope stopped, the red dot was EXACTLY over the planent. Looking through the eyepiece had Jupiter almost spot on smack in the middle of my 25mm eyepiece.

Bill Cosby voice mode: "Now that's what i'm talking about !"

I then entered M13 and again, ended up with the object almost centered in the eyepiece. That's defenitely good enough for me. And the scope is not even polar aligned ! I guess GOTO performance must be even better if the optional polar wedge would be used.

So I think the combination of not leveling the tripod properly plus a certain amount of backlash in the gears was the reason for my disappointing experience the other night.

the first night out

This weekend i took my new telescope for a test drive outside on top of my garage. So here is how it went:

Telescope alignment
During my research i had stumbled on a couple of forums where people were reporting problems using the SkyAlign feature. It was pointed out that in order to have this feature work properly, you need to make sure that the telescope is placed perfectly horizontal/level to the ground.

I did that using the bubble level that comes with the telescope. I also checked it again using the carpenter app on my iphone. From what i could tell, the tripod was more or less level. (this "more or less" bit would bite me in the butt later...)

I attached and plugged in the dew cap and after a couple of minutes i could feel that it was getting slightly warm. So far so good !

So i started the SkyAlign feature and after entering my location, time and date, I chose Jupiter and Arcturus as my first two objects and then just picked some star that was in between the two. The hand controller showed a rotating line for a couple of seconds and then said something like "aligment confirmed". (too bad that it does not have the star trek computer voice or Mr. Worf stating this out loud, like "captain - stellar aligment confirmed !")

Whooopdi-doo ! Finally something that works after the first try ! Needless to say, i was quite proud of myself...

With alignment completed, i immediately pressed the "M" button on the remote and entered "M13" and the telescope started its GOTO thing going "whhiiirrrr..rrr..rrr" with me blissfully watching it go. Then it stopped. I looked through the eyepiece and saw: nothing.

DANGIT !

I moved the telescope left and right and then found M13 quite a ways off and centered it in the eyepiece. After a while i noticed that it had started to move off to one side. So obviously something was not quite right. So i used the SYNC feature to tell the telescope that i was indeed looking at M13. I then hit the "Planets" button and selected "Jupiter". And the marvels of GOTO started to swing the telescope in the direction of Jupiter. Jupiter ended up just slightly out of view of my 25mm eyepiece.

DOUBLE-DANGGIT !

So i decided to use my 40mm wide field eyepiece and spent the night cruising the sky quite happily, but not at all satisfied with the GOTO feature. I also noticed that it took quite a while for the telescope to move in certain directions after i had pushed the movement buttons on the controller. This supposedly is called "backlash" and i decided that i would read up on the matter the next day.

So hang on for part TWO, where things looked ALOT better : )

telescope setup

So after i had moved all the boxes out of the way, it was time to assemble the telescope, which turned out to be much easier then what i remembered from setting up the LX-10 many years ago.

There's a nice color "quick setup guide" that comes in the box. It nicely illustrates all the necessary steps. There are setup videos on youtube as well. Some of them look like they are produced by Celestron themselves. Just search for "Nexstar setup" and a bunch of movies turn up.

Tripod

I first put up the tripod, which is surprisingly light and almost flimsy compared to my heavy meade field tripod on the LX-10. Attaching the accessory tray was easy using the detailed "quick setup" descriptions. I wonder how this much lighter tripod will handle out in my backyard. I'm a little afraid it might be too light...

Optical Tube

Next came the optical tube assembly (also called "OTA"). The optical tube came packed with the mirror pointing down at the bottom of the single fork arm which made it a little harder to lift it onto the tripod. I quickly checked the manual if the tube could be moved manually. It said that this could be done, so i moved it to a 90 degree angle and then put it on top of the tripod. (since i originally wrote this blog entry, lots of people have told me that the OTA should really not be moved manually - one should always move it while powered and by using the hand controller)

There are three screws that stick through the top of the tripod that fit right into the bottom of the scope. One of them could not be screwed in all the way, even after removing the telescope from the tripod serveral times and re-arranging it on the tripod.

Even with one of the three screws only partially screwed in, i decided not to spend any more time fiddling with that last stubborn screw. There were two or three strips of tape accross the hand controller and the optical tube cap that had to be removed.

Starfinder finderscope

Next came the Starpointer finderscope. The instructions said that it should be installed by sliding it over the fitting on the OTA. After several tries i could not get it to fit and had to get a screwdriver to slightly loosen the bottom part so that it would slide onto the fitting. The starpointer is made from plastic and i wish it would be made from metal. The future will show how well it holds up.

Star diagonal and eyepiece

The star diagonal seems to be very good quality and (i think) does not incorporate any plastic parts like the Meade diagonal did that came with the LX-10. The 25mm eyepiece seems to be of a good quality as well, but i'm no expert and i guess i'll just have to wait for the first night out to see if i like it or not.

Kendrick heated dew cap
This heated dew cap (item Nr. 2032.ZC) does not come with the telescope - i ordered it separately. I think that a heated dew cap is a very important and necessary item if you want to observe for a couple of hours without having to worry about getting your telescope all fogged up. Especially in spring and autumn. I once took my LX-10 to a friends house with a big crowd waiting to marvel at the sky only to realize, that everything was covered in dew which turned the telescope unusable.

This dew cap is quite a bit smaller than the one i was used to on the 8" SCT but otherwise looks to be of great quality as well. It works the same way as my old dew cap by using a velcro strip to fasten the cap around the optical tube. It all fit perfectly the first time i tried it. The first night out will show if it works as advertised.

adventures in unpacking

Last friday, my new Nexstar 6 SE telescope arrived via UPS. My wife sent me an SMS saying "one HUGE box arrived today - it must be your new telescope !". I had to reign in my excitement until after the kids had gone to bed so that i could unpack and assemble the scope in peace and quiet.

I had ordered the following items:

• Nexstar 6 SE telescope
• Kendrick heated dew cap with 12V adapter cable
• 12V adapter cable to power the telescope

A box, in a box in other box
The telescope arrived in one single box. Inside was another box, which then had four more boxes inside. That's a nice stack of empty boxes i had lying around when everything was upacked. Here's what was in the boxes:

1. biggest box - optical tube, nicely protected in a styrofoam case
2. longest box - tripod with a kendrick heated dew shield, which i had ordered separately
   
3. two small boxes - eyepiece, star diagonal and the other box was disappointingly empty

"that looks like it's really good quality"
That's what my wife said when i had everything upacked and had moved the boxes out of the way. She especially liked the heavy single fork arm and was glad that the optical tube was not as orange as the ads on the internet had let us believe : ) And i had to agree - so far everything looked very nice with good packaging and no loose parts flying around in any boxes. The optical tube was covered in an extra layer of paper which had to be removed. There were no visible marks or scratches of any kind on either the optical tube or on the tripod. I had read other reviews on the internet where this was not the case - so i guess i got lucky.

Unfortunately, the 12V power adapter was missing but a quick email later, it was shipped out and should be on the way.

This time around i put all the boxes up in the attic so that i could use them again if need be. Something i did not do when i got the LX-10.

So now i just had to wait for a cear night out to test my new GOTO telescope !

...unfortunately i was too excited and eager to assemble the scope so i forgot to take pictures while unpacking.

so why the Nexstar 6 SE ?

I originally had bought a Meade LX-10 8" Schmidt Cassegrain telescope in 1998. This scope has great optics but was very heavy, since i had opted for the Meade heavy field tripod and not the regular one. I updated the scope with a crayford focuser in 1999, a heated dew cap from Astrozap.com in 2002 and a Meade Magellan 1 astrocomputer in 2005. I added the astrocumputer because it took me longer and longer to find certain objects in the sky but i did not feel like buying a whole new telescope.

For the last couple of years i found myself less and less wanting to always lug the whole telescope and tripod out onto the garage, so i finally decided to sell the LX-10 on ebay. After only a week, the telescope was sold. Oh boy - so now i had to figure out which telescope to get. Over the years i had always marveled at those ads from Meade or Celestron with their cool GOTO scopes.

So i started to read tons and tons of reviews on the internet about current GOTO telescopes. Maybe someone at Meade or Celestron might have noticed a sudden spike in google search terms for "meade ETX" or "Nexstar SE". I also looked at Meade's brand new LS series with integrated (!) CCD camera, but although it would probably be a very cool telescope, the price was just not in my ballpark. I finally decided that my new telescope should meet the following criteria:

1. it should be alot lighter than the old LX-10
   
2. it should have full GOTO capability
3. it should have a maximum aperture of 6 inches
4. it should be possible to attach my new panasonic Lumix G1 camera for very basic planetary as well as astrophotography
5. it would be great if i could still use my crayford focuser
6. the price should be around 1000 swiss francs / approx 950 USD

After reading alot of reviews, it was down to the Meade ETX 125 and the Celestron Nexstar 5SE or 6SE. Since i had already owned a product from Meade, i decided that i'd go with Celestron this time. And i have to admit, i thought that the Nexstar SE series with the single fork arm mount with the integrated hand controller really looked so cool ! I'm a gadget freak after all....

The fact that the 6SE comes with a better/heavier tripod and it's larger size compared to the 5" version while still being very portable, finally had me decide on the Nexstar 6SE. The next weeks and months will show if it was a good decision or not...

Telescope prices are ridiculously high in Switzerland. I found an online store in Germany called "teleskop-express", which had by far the best prices and seemed to really know what they're doing. I even got a special bundle offer.

So here i am waiting for the UPS van to arrive....

Addition January 18th 2010: I've now used the telescope for the last couple of months and can now say that it's a superb telescope for visual work. If you plan to do any long exposure astrophotography, then you need an equatorial mount. Celestron offers one called CG-5 and one that is more expensive called CGEM.

Right now the alt-azm mount that my 6SE offers will be great for visual and short exposure work, and that's all i trust myself with right now. But i can already see that should i want to get into serious photography, then a different mount is a must.