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Setting up a Celestron Edge HD11 for CCD

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#1 Jeff Struve

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Posted 31 October 2012 - 10:59 AM

Just getting ready to purchase the subject OTA and another Atlas mount... other than getting the larger mount head and a couple extra weights for the Atlas... what else should I be getting to use my CCD on this critter?

Somewhere I thought I read about using a crawford focuser... thanx!

#2 WarmWeatherGuy

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Posted 01 November 2012 - 01:21 AM

I can't imagine doing astrophotography without a Bahtinov mask. The ones by Farpoint easily rest on your dew shield.

#3 Jeff Struve

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Posted 01 November 2012 - 07:54 AM

Thanx... that might be a good idea for my other OTA's as well...

#4 EFT

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Posted 01 November 2012 - 11:17 AM

I would at least recommend a dual speed primary focuser. A "crayford" can also be handy, but you have to watch out for back focus issues with the Edge HD scopes depending on the imaging system due to the optimatized focal plane distance with these OTAs. I would also highly recommend motorizing the focusing.

In addition, expect the C11 to be a real challenge for imaging on the Atlas mount, particularly at prime focus. You are in the upper load range for that mount and at f/10 it will be a real challenge. You will want to make sure that the mount is working at its best. I would personally recommend the C9.25HD over the C11 with the Atlas mount.

#5 JMW

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Posted 01 November 2012 - 08:49 PM

If you are using the scope at native focal length, you should consider an off axis guider. I found it frustrating to image with it using a 2nd guide scope. My mount wasn't the problem, it was mirror flop. I have an AP900GTO. I can do 20 minute plus exposures with the OAG.

#6 wolfman_4_ever

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Posted 01 November 2012 - 10:16 PM

The $600 0.7x focal reducer.

#7 korborh

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Posted 02 November 2012 - 12:08 AM

+1 on OAG. For long exp imaging.

#8 freestar8n

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Posted 02 November 2012 - 03:30 AM

I agree that OAG would be the best way to guide, and that the 0.7x reducer would make it easier to get good results with an Atlas. Either way, I would only add an extra focuser for visual work where you want a good "feel" as you go in and out of focus. Otherwise I would instead spend the money on Robofocus and use the primary focuser that is already provided - coupled with autofocus software. The primary focuser is perfectly adequate for good focus, and autofocus software can take care of any backlash in the mechanism and find focus automatically.

Frank

#9 Jeff Struve

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Posted 02 November 2012 - 06:14 AM

Thanx all... a few questions:

OAG -
I have heard good and bad about OAG... I have the SBIG STi with their guide kit and thought that would be the way to go because a) no flexure in that it uses a clam shell rather than a ring system b) light weight c) an OAG restricts you to only what it sees via the primary d) no stealing of light e) any concerns with additional focus issues if you add a filter wheel f) concerns regarding the overall length of the OTA and camera set up and bumping into the mount legs... Can I get the OAG Pro's from you?

Dual Speed Primary Focuser -
I am not sure what to do here... are you meaning that there is a dual speed replacement for the stock focus knob, or is there a better choice in dual speed focusers that you suggest?

Motorized Focus -
I do have RigelSystems motorized step motor and PC controlled focusers that I can control with MaximDL on my 12" dob and 80mm and 127mm refractors... I haven't checked out what Leon has for the HD11, but did plan on going that route... are you thinking that if I do this that the stock focus is fine? I guess that would make sense...

0.7X Focal Reducer -
I am not sure what the reducer will do for me to help... I have heard about these before but don't recall exactly what they/it would do... can you give me a high level idea on this?

f/10 vs f/2 -
I have heard that this OTA is set up to some how facilitate both f/10 and f/2... I need to read up more on what this can do for me and how that feature is implemented...

Thanx all!

#10 WarmWeatherGuy

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Posted 02 November 2012 - 11:28 AM

This video How to focus a wobbly telescope might help you decide if you want a motorized focuser or not.

#11 Jeff Struve

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Posted 02 November 2012 - 12:01 PM

Very cool video on the mask! Actually, I can see how you might be able to get away from a motorized focuser by using the mask... but then again, what a great combination... you can use the motorized focuser to eliminate movements while aligning with the ask... and when you get it right, the motor will keep the focuser in place and prevent any mishaps from occuring ...

Is there a place that I can get templates? Althought I think it may be better just to buy them so they can be made out of a more durable material than cardboard...

Thanx!

#12 WarmWeatherGuy

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Posted 02 November 2012 - 12:19 PM

There are some links in the video description that talk about how to make your own mask.

http://www.deepskywa...tinov-mask.html
http://www.skyatnigh...m/bahtinov-mask

I prefer the ones by Farpoint
http://www.telescope...es/photograp...
because they easily sit on your dew shield. The masks that have a huge hole in the middle are meant to rest on your corrector plate with the secondary mirror poking through the hole. To me this is a really bad design. You would have to stand on a ladder to reach down through your dew shield to remove the mask. In addition you would have to take off your gloves and be careful not to touch the corrector plate. Even without a dew shield the Farpoint mask is easier to put on and take off.

I use my telescope mostly for imaging. For those who use it visually I can see the appeal of a motorized focuser. It would be a pain to have to go to a star to focus just to look at the Moon. If I am imaging the Moon though I will go through the trouble because I want the picture to be perfect.

#13 rigelsys

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Posted 02 November 2012 - 01:08 PM


Hi Jeff,

I have bracket and gears for the HD11 (tho will need some standoffs added to stepper motor for spacing, unless you get a new stepper which comes with them).

Have a customer in Virginia getting good results with a setup like you're considering.

http://www.pbase.com/skybox


Leon

Thanx all... a few questions:

OAG -
I have heard good and bad about OAG... I have the SBIG STi with their guide kit and thought that would be the way to go because a) no flexure in that it uses a clam shell rather than a ring system b) light weight c) an OAG restricts you to only what it sees via the primary d) no stealing of light e) any concerns with additional focus issues if you add a filter wheel f) concerns regarding the overall length of the OTA and camera set up and bumping into the mount legs... Can I get the OAG Pro's from you?

Dual Speed Primary Focuser -
I am not sure what to do here... are you meaning that there is a dual speed replacement for the stock focus knob, or is there a better choice in dual speed focusers that you suggest?

Motorized Focus -
I do have RigelSystems motorized step motor and PC controlled focusers that I can control with MaximDL on my 12" dob and 80mm and 127mm refractors... I haven't checked out what Leon has for the HD11, but did plan on going that route... are you thinking that if I do this that the stock focus is fine? I guess that would make sense...

0.7X Focal Reducer -
I am not sure what the reducer will do for me to help... I have heard about these before but don't recall exactly what they/it would do... can you give me a high level idea on this?

f/10 vs f/2 -
I have heard that this OTA is set up to some how facilitate both f/10 and f/2... I need to read up more on what this can do for me and how that feature is implemented...

Thanx all!



#14 Jeff Struve

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Posted 02 November 2012 - 02:08 PM

Thanx Leon... you are catching on to my modus operendi... ;)

I'llget the bid from you via email!

#15 rigelsys

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Posted 02 November 2012 - 05:15 PM


0.7 Focal reducer will give you wider FOV and smaller star images. The FOV for the HD 11 is pretty small, you'll look right through some open clusters!!! If your HD field is flat enough far enough out, you might find it enjoyable. And besides they're pretty cheap.

with nSTEP on primary focus knob won't need dual speed there. Some people prefer to add a crayford in addition, to minimize image shift ... which is noticable but small and also because of concerns of running a "V" curve when focusing by moving the mirror forwards/backwards with the primary focus knob. Can solve that by approaching focus from same direction each time (raising mirror against gravity). Can also do this during temperature compensation (Sequence Generator supports that). The link I sent you for the hole in the trees skybox does it that way.


Thanx all... a few questions:

OAG -
I have heard good and bad about OAG... I have the SBIG STi with their guide kit and thought that would be the way to go because a) no flexure in that it uses a clam shell rather than a ring system b) light weight c) an OAG restricts you to only what it sees via the primary d) no stealing of light e) any concerns with additional focus issues if you add a filter wheel f) concerns regarding the overall length of the OTA and camera set up and bumping into the mount legs... Can I get the OAG Pro's from you?

Dual Speed Primary Focuser -
I am not sure what to do here... are you meaning that there is a dual speed replacement for the stock focus knob, or is there a better choice in dual speed focusers that you suggest?

Motorized Focus -
I do have RigelSystems motorized step motor and PC controlled focusers that I can control with MaximDL on my 12" dob and 80mm and 127mm refractors... I haven't checked out what Leon has for the HD11, but did plan on going that route... are you thinking that if I do this that the stock focus is fine? I guess that would make sense...

0.7X Focal Reducer -
I am not sure what the reducer will do for me to help... I have heard about these before but don't recall exactly what they/it would do... can you give me a high level idea on this?

f/10 vs f/2 -
I have heard that this OTA is set up to some how facilitate both f/10 and f/2... I need to read up more on what this can do for me and how that feature is implemented...

Thanx all!



#16 Jeff Struve

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Posted 05 November 2012 - 12:52 PM

I placed the order for the HD11 yesterday... next week I am planing on ordering the rest of the gear... the Atlas Mount and AC adapter, 2 additional counter balance weights, an ADM Plate Adapter, the Starizona Hyperstar, 4 Batinov masks (1 for each of my OTA's), and the RigelSystems nSTEP with buttons & stepper motor...

Short of buying a hunk of ground for a permanent structure... I think I am seeing light at the end of new OTA's! ;)

Thanx for all of your help!

#17 rigelsys

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Posted 06 November 2012 - 01:14 PM

Hi Jeff,

You might ask the dealer to open it up and plug it in and make sure the GPS is working. My CPC 11 brought straight home from Celestron factor (20 minutes from my home) had a dead GPS. I took it back into the factory and they took a month to fix.

I don't think you'd enjoy shipping it in to the factory for repair, from Missouri!

I placed the order for the HD11 yesterday... next week I am planing on ordering the rest of the gear... the Atlas Mount and AC adapter, 2 additional counter balance weights, an ADM Plate Adapter, the Starizona Hyperstar, 4 Batinov masks (1 for each of my OTA's), and the RigelSystems nSTEP with buttons & stepper motor...

Short of buying a hunk of ground for a permanent structure... I think I am seeing light at the end of new OTA's! ;)

Thanx for all of your help!



#18 Jeff Struve

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Posted 06 November 2012 - 01:30 PM

Thanx Leon... i assume that the GPS issue was mount related? I won't be getting the CGEM or Celestron mounts... i want to use the Orion... hoping it will handle everything... if not, then I might have to go Celestron, in which case I'll take your advise!

Thqnx for keeping watch!

#19 rigelsys

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Posted 06 November 2012 - 02:20 PM

Hi Jeff, you're right it's mount related (my bad)

#20 Jeff Struve

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Posted 10 November 2012 - 11:32 AM

Another question before I finish the purchase of the other gear next week...

Why would I want the Starizona Hyperstar... I know that it turns the HD11 from F10 into an F2... but I already have an 80mm triplet refractor... ????

#21 WarmWeatherGuy

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Posted 10 November 2012 - 11:38 AM

The exposure time goes with the ratio of the f numbers squared. Going from f/10 to f/2 is a ratio of 5 so you would need 1/25th the time. This makes tracking way easier. Your refractor might be f/6 so it would be 1/9th the time when compared to that.

#22 Jeff Struve

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Posted 10 November 2012 - 11:45 AM

Ah... so what you are saying is that the C11 at F2 will take the same pic I can take with the 80mm but the C11 would allow it done with much shorter exposure times?

#23 WarmWeatherGuy

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Posted 10 November 2012 - 11:49 AM

Yes. They would both have about the same focal length so the field of view would be about the same but the C11 would collect way more light.

#24 Jeff Struve

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Posted 10 November 2012 - 11:52 AM

I really appreciate that explanation.... I am not sure if I should put the $$$ into the Hyperstar like I planed or something else... that really sounds enticing to take shorter exposures tho...

#25 rigelsys

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Posted 10 November 2012 - 07:50 PM

With bigger aperature it will be brighter and resolution will be finer. or so theory says. Shorter exposure times, sharper stars






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