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Celestron 8SE + DSLR and free movement question (not hitting the alt/az base) possible fix?

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#1 markm75c

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Posted 09 January 2019 - 03:06 PM

Can anyone comment on what the easiest way to make it so that if i have the Canon 6D + Ring Adapter + Tring + maybe a spacer if needed + f6.3 reducer then the 8SE scope, that i can be sure the camera wont hit into the fork of the alt/az mount.. or can this even be done.

 

Does this involve, i think it was dovetail or similar, a longer one or piggy backing one, so the tube can shift more upward (if you view it in its vertical clearance position)?

(Such as this 7" one):  https://www.highpoin...te-7-long-vdup7

 

Anyone had any experience in modifying this to work and can recommend the part needed?

 

Thanks in advance



#2 Noah4x4

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Posted 09 January 2019 - 04:04 PM

A wedge would give you a bit more back end clearance and also help you avoid field rotation, otherwise I don't think there is a solution beyond repositioning your OTA as far forward as possible. Fork mounted Alt-Az mounts are not ideal in this context. 

 

However, I found using a wedge frustrating, tedious and cumbersome and eventually I switched to Hyperstar; hence mounting my camera in the place of the secondary mirror at the front of the OTA on my (Alt-Az) Evolution. Then no clearance issues, no need for polar alignment or autoguiding as Hyperstar produces images 28x faster.

 

The poor experience with the wedge also convinced me NOT to replace my Alt-Az with a GEM as polar alignment took too long. Given breaks between clouds are short at my location I wanted more time observing and less time fiddling with equipment. It was a clear cut decision, buy an AVX or Hyperstar at similar price. I don't regret the latter, and an 8SE is similarly 'Fastar compatible'. My advice, persevere with where you are; accept limited clearance; don't buy wedge/GEM and when budget permits consider Hyperstar. 



#3 markm75c

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Posted 09 January 2019 - 04:47 PM

A wedge would give you a bit more back end clearance and also help you avoid field rotation, otherwise I don't think there is a solution beyond repositioning your OTA as far forward as possible. Fork mounted Alt-Az mounts are not ideal in this context. 

 

However, I found using a wedge frustrating, tedious and cumbersome and eventually I switched to Hyperstar; hence mounting my camera in the place of the secondary mirror at the front of the OTA on my (Alt-Az) Evolution. Then no clearance issues, no need for polar alignment or autoguiding as Hyperstar produces images 28x faster.

 

The poor experience with the wedge also convinced me NOT to replace my Alt-Az with a GEM as polar alignment took too long. Given breaks between clouds are short at my location I wanted more time observing and less time fiddling with equipment. It was a clear cut decision, buy an AVX or Hyperstar at similar price. I don't regret the latter, and an 8SE is similarly 'Fastar compatible'. My advice, persevere with where you are; accept limited clearance; don't buy wedge/GEM and when budget permits consider Hyperstar. 

Yeah i never liked the wedge options and for right now i really didnt want to move to a GEM just yet due to cost / until i move/ build an observatory once re-located.

 

I had been looking at the hyperstar as an option though..  Though i was thinking in terms of moving to an 11 or even 14" edge celestron with hyperstar.. i only know very basics of it, except it makes things for deep space work on the same telescope without buying a refractor (some seemed to frown on this concept of avoiding a refractor but i'm starting to see alot with very good results).

 

Perhpas i should consider staying at the 8" longer term and getting a hyperstar ($999 i think).. so in doing this i guess from what your describing, the camera doesnt end up in the way or using a ccd?  My question on the hyperstar is, how quickly can you take it off and go back to normal long focal length (planetary) mode?  If its an ordeal, i guess thats not so ideal..  then i still end up thinking of possibly building a roll off roof observatory with 2 mounts, one for planetary and one for DSpace?

 

I was hopeful that piggy backing another dovetail would make things be clear near the base.. in winter months i like to be able to remote control the scope sitting outside via teamviewer, but dont want to risk choosing a target out of range.. though i guess i could figure out a limiting slew percentage and just set it.


Edited by markm75c, 09 January 2019 - 04:48 PM.


#4 Noah4x4

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Posted 09 January 2019 - 05:33 PM

One issue with Hyperstar is it is aperture specific. So you can't migrate an 8" to an 11". However, I am delighted with the results on my 8". But you might wish to defer Hyperstar purchase until you do get the larger OTA. 

 

Changing over from F/10 to Hyperstar (and back) is easy.

1.  Unscrew Fastar ring around secondary mirror.

2.  Place secondary mirror in supplied protective case.

3.  Screw Hyperstar onto Fastar fitting.

4.  Screw camera onto Hyperstar.

5.  Connect cables.

6.  Remove diagonal/eyepiece and replace with counterweight.

 

This takes me about a minute. I then do a Starsense Auto-Align (two minutes). Because the FOV is x5 it is nigh on impossible for your target object to be outside FOV. Compared to polar alignment Hyperstar is a joy to set up. Whilst not unbreakable, your corrector plate is surprisingly robust. So, do not fear adoption of Hyperstar.

 

I too remotely control my scope and it's much easier (IMHO) with Hyperstar because of the FOV. You have zero fear of your expensive camera hitting your mount and setting regular slew/cordwrap limits is the only precaution you need. However, I recommend using Cat6a cable rather than wireless which can be flaky and may cause wild uncontrolled slews. However, your camera is much better protected when affixed to Hyperstar on the front end as it would be the OTA that would now hit the mount rather than camera. 

 

When reverting to visual, you just reverse these steps. You will not lose secondary mirror collimation as the secondary mirror has a grub screw that drops into a locating slot. Again, a minute to changeover. 

 

Having bought an Evolution, I ran into all the issues expected of an Alt-Az. Rather than buying a GEM, Hyperstar offered me the best solution  (albeit I did try a wedge and wasted £300 on that infernal device). I hope this is helpful. 


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#5 markm75c

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Posted 10 January 2019 - 10:43 AM

One issue with Hyperstar is it is aperture specific. So you can't migrate an 8" to an 11". However, I am delighted with the results on my 8". But you might wish to defer Hyperstar purchase until you do get the larger OTA. 

 

Changing over from F/10 to Hyperstar (and back) is easy.

1.  Unscrew Fastar ring around secondary mirror.

2.  Place secondary mirror in supplied protective case.

3.  Screw Hyperstar onto Fastar fitting.

4.  Screw camera onto Hyperstar.

5.  Connect cables.

6.  Remove diagonal/eyepiece and replace with counterweight.

 

This takes me about a minute. I then do a Starsense Auto-Align (two minutes). Because the FOV is x5 it is nigh on impossible for your target object to be outside FOV. Compared to polar alignment Hyperstar is a joy to set up. Whilst not unbreakable, your corrector plate is surprisingly robust. So, do not fear adoption of Hyperstar.

 

I too remotely control my scope and it's much easier (IMHO) with Hyperstar because of the FOV. You have zero fear of your expensive camera hitting your mount and setting regular slew/cordwrap limits is the only precaution you need. However, I recommend using Cat6a cable rather than wireless which can be flaky and may cause wild uncontrolled slews. However, your camera is much better protected when affixed to Hyperstar on the front end as it would be the OTA that would now hit the mount rather than camera. 

 

When reverting to visual, you just reverse these steps. You will not lose secondary mirror collimation as the secondary mirror has a grub screw that drops into a locating slot. Again, a minute to changeover. 

 

Having bought an Evolution, I ran into all the issues expected of an Alt-Az. Rather than buying a GEM, Hyperstar offered me the best solution  (albeit I did try a wedge and wasted £300 on that infernal device). I hope this is helpful. 

Yeah i knew you couldnt migrate.. i doubt these can be found used at the moment, but maybe if i eventually get the 8 for now (hyperstar) i could then sell and find a used one for the 11 or 14 depending.

 

The secondary mirror part always sounded a bit scary but i guess from what you are saying its not too bad.

 

Are you remote controlling yours via teamviewer or how exactly.. running a cat5 or cat6 wouldnt be too bad aside from running it through my house's office window somehow (more permanent would be more ideal, probably in a pipe underground, but thats a bit of digging from about 85 feet away.  

 

On the alt/az vs GEM.. you dont feel theres really a need for a GEM for DS astro now that you have the hyperstar?  Wouldnt long term exposures over hours (to get brighter better pictures) still be needed even if single exposures are "faster" with the shorter focal length?  I would think over the course of several hours that the scope would drift and need realigned?  I guess for planetary it may still be fine without the GEM option.  It would be nice to think i wouldnt need to throw more cash at the system in the long run, but i would need to change mounts for the 11 or 14 edgehd.

 

Oh and now there is an official remote controllable focuser by celestron for celestron otas ($200).. probably going to jump on that.. or.. maybe not that needed given once you get it in focus it should stay there (or does it).. just now getting into longer duration captures, so i guess ill find out



#6 Noah4x4

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Posted 10 January 2019 - 02:12 PM

Yes, removing secondary mirror and replacing it with Hyperstar is easy and you won't lose collimation.

 

Remote control.....arrgghhh.....yes....but I over engineered this!!!!!

 

I was initially obsessed with 'wireless' and 'cordwrap free', but my camera exceeds 4k UHD and I also wanted to hook up to a 4K UHD monitor. I succeeded by putting an Intel NUC i5 with Iris Plus 640 Graphics at the scope and another NUC indoors, the latter controlling the former via Windows Remote Desktop. To get there I had to resolve a bucket load of challenges, but I did produce an 'end to end' 4K UHD wireless system. However, despite having invested in the highest quality components and establishing a 'peer to peer' 5Ghz Astro dedicated network with no external interferences I still suffered from occasional frustrating 'lag' and less frequent 'drop outs'. The danger with this is the risk of a wild uncontrolled slew and potential damage to one's rig. 

 

Wireless using Windows Remote Desktop (or TeamViewer) works fine with (say) 1080p 'HD' cameras, but step up to a large sensor, ultra high definition 'UHD' (4k) camera and frankly, current consumer wireless technology (802.11ac) is unreliable.  People pursuing these ambitious goals do need to understand the limits of current connectivity technology (or not buy the highest resolution data intensive cameras) for EAA.  

 

I then replaced wireless between the two NUCs with 'active' USB3 cable. Works fine, but only up to about 10M. I also suffered conflicts between USB3 and USB2 devices.  So I then switched to a 20M Cat6a cable and that works perfectly. However, rolling out the Cat6a cable on every use soon puts kinks in it and it becomes ever more tricky to coil after use. It's perhaps better for a permanent observatory as I am not convinced how robust it will be if in daily temporary use. However if you require perhaps 30M distance or beyond, it is arguably the only solution if your camera data transfer demands are extreme.

 

Here, Astrophotographers will be quick to jump in and say that you only need a high powered computer at the scope as you only need use the second computer to control the former and any post -processing can be done on the primary. That is absolutely true for AP.  But for EAA the objective is immediate 'near live' viewing.  So if you want to benefit friom a 4K UHD display (monitor), the computer at the terminal point of the system must be 4K UHD graphics capable. Hence, one is squeezing 4K UHD screen data down the wires. EAA and AP demands hence differ if you seek 4K UHD. I would add that 1080p EAA is great, but what is the point of buying a 'UHD' camera to output to a mere 'HD' display? Also if you embrace Hyperstar, the higher <zoom> capability of a 3,840 x 2,160 display is beneficial as the benefit of a 5x increase in FOV is at the inevitable cost of a reduction in magnification.

 

Eventually (and this will sound utterly stupid given the complexity of earlier efforts), I tried running a 20M (65 feet) HDMI cable from the NUC at scope direct to my monitor indoors. I now control the NUC at scope by a Logitec wireless keyboard/mouse which has a truly remarkable range. This works just as well as any of the above up to 20M and saves the cost of a second computer. But over how much further distance a HDMI cable will work beyond that is debatable. However, it's so cheap I would try over your 85 feet. Frankly, I  went down this low cost route after belatedly discovering that you NEVER actually need two computers as a single computer plus mere 'AV/HDMI extender' using cat6a works over quite long distances. Until then, the simplicity of attempting wireless mouse/keyboard and HDMI didn't even cross my mind. Now I have a surplus NUC, but will find an alternative use!

 

In summary, don't be lured into the wireless/cordwrap free paradigm until you have really thought everything through. I totally over engineered things and wasted a tonne of money. However, I suspect that my experiences can benefit others. Best of luck! 

 

Lastly, I am sure a GEM is beneficial if you want to win Astrophotographer of the year and sit for hours chasing a single remarkable exposure.  But you enquired about EAA where an Alt-Az + Hyperstar is far easier, is light pollution beating and is about near live observing, and not about taking pictures (although you can). Unless you want to get drawn into the dark arts of AP there isn't any need to fall into an even deeper money pit (yes, been there too with my wedge!). For EAA you don't need polar alignment or autoguiding, just a few stacked 20 second frames even to view the Horsehead. But if you want an award winning image, then you may need long exposures. 


Edited by Noah4x4, 10 January 2019 - 02:45 PM.

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#7 pepperonihead

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Posted 13 September 2019 - 11:37 AM

So, from what I have heard with an 8 inch aperture scope you cannot use Hyperstar with a DSLR like my Canon 70D. Evidently the DSLR is too big. Is that correct? I would like to get the hyperstar for my 8 inch Celestron CCP but I would much rather just use my Canon 70D as the camera rather then having to buy another expensive CCD camera. 




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