I have an Orion Sky View Pro go to mount (GEQ) and a 203 mm reflector tube, a 150 mm Mak- Cas tube (primary), a Nikon d-40 DSLR, and an SBIG ST2000 XCM (primary) camera.
My main problem is tracking. Regardless of how careful I am with the polar alignment, I cant go beyond a 25 second exposure before trailing.
I bought the SVP mount and then added the goto system later. I believe I may have the motor gears improperly aligned with the mount. (They have a huge disclaimer in the manual of the go to kit).
--- Is there a GEQ mount with at least an 11 inch SCT that comes with the motors preinstalled and calabrated for under $5,000.00? ----
Thank you for taking the time to share your experience with me.
2007-11-22
15:54:15
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6 answers
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asked by
kiseek
3
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Science & Mathematics
➔ Astronomy & Space
Thank you - laurahal42 - ! I have been on a quest for a better mount than the Orion SVP that I'm currently using.
Even though my SBIG has dual CCD's, one for imaging and one for tracking, I am forced to use the T & A feature (Track and Accumulate) with the specs being 22 seconds X 65 shots with dark frame use every 5th image..
I am shooting for 10 minute exp x 4. That being said, thank you once again, laurahal42, for the name of a much better mount than the one I own.
Much appreciated!
__ Wishing you clear skies and Moonless nights,
.... Kiseek
2007-11-22
16:50:15 ·
update #1
You've already answered your question: if you can't track the stars accurately, it doesn't matter what telescope you're using.
Many astrophotographers (including your truly) use Losmandy mounts. I have a G-11 and take pictures through a 5" apo refractor (with an external guide scope), and an 8" SCT (with an off-axis guider). It works fine.
How are you aligning your mount? I align my G-11 with the polar scope, then do an iteration or two of drift alignment. I have no issues with stars trailing.
2007-11-22 16:05:21
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answer #1
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answered by laurahal42 6
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As already stated, in imaging it is the mount that becomes the single most important part of your set-up.
"I can get very good images with a mediocre Telescope on a good Mount, but the opposite is definitely not true"
Having said that, I have been using the EQ-5 mount (AKA Orion Sky view Pro, it is sold under many labels) for imaging for years and have no problem getting 10 minute exposures.
The key is a good Polar Drift alignment and a well - calibrated guiding setup. As with any mount, Periodic Error Correction Training (PEC) is very important.Just make sure you save it when you shut down your mount.
The load limits of any mount when used for imaging is always less than the stated load limit which is for visual use.
The SVP mount will handle the Mak-Cass with no problem, but you're stretching it with the 8" Newtonian.
The simple truth is that, when it comes to imaging, there is no such thing as a mount that is too big.
So you get the biggest and best that you can afford.
Since in my 45+ years of Astronomy I have never had any money to speak of, cost was always a prime consideration.
With that in mind, what are your choices??
For Newtonians and Telescopes of comparable weight, The Orion Sirius mount will handle an 8" scope beautifully. The Orion Atlas (AKA Eq-6) will handle a 10" Newtonian or equivalent. ( This is the setup I am using right now.
Anything larger than this and you are getting into very expensive Territory, such as Astrophysics mounts or the Bisque mounts which start in the $10,000.- and up (way up ) region.
The current crop of the EQ mounts sold by Orion, Skywatcher and others are the full equivalent in performance of the Vixen and Losmandy Mounts. very solidly built. but not as pretty as some of the others, they represent by far the biggest bang for the buck.
Don't get me wrong, I go green with envy when I look at my Friend's Astrophysics 900 goto mount, it is a thing of beauty. But since I don't have $20 grand to spare, I'll use my Atlas, even if i may have to work a little harder.
By the way, exposures of 5 to 8 minutes or so is all you can expect from any portable mount. It is a different story with a permanent Installation. Our 12" Meade at the club is so accurately aligned, it will do that UNGUIDED.
I hope this helps a little.
Adolph
2007-11-23 05:44:18
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answer #2
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answered by Adolph K 4
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You modern astrophotogrophers are so lazy. You have to hand guide! You use a guide scope (large, high power finder), or a beam splitter or small mirror that catches a corner of the field of view from the main telescope and directs it to another eyepiece, and you arrange to have a star (a "guide" star) sit on the cross hairs of your guide eyepiece, and then you have to look at it all during the exposure and make manual adjustments with the slow motions as needed all the time during the exposure to keep that star exactly on the cross hairs. I have done that for up to 90 minutes at a time, back in the days of film astrophotography. What a chore! If that is too hard, there are guiding cameras, that interface directly to your mount's controls and do the guiding for you. They either are separate cameras to be mounted on a guide scope or an imaging camera with 2 CCDs, one for taking the image you want and the other looking at guide stars.
2007-11-23 00:21:01
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answer #3
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answered by campbelp2002 7
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Your mount is the weak link in your setup, and that's what you need to upgrade. EQ-5s, at least until recently, simply don't have the precision needed for serious astrophotography. I'll second the recommendation for the Losmandy G-11. I had one of these for a few years and it was a beautiful and precise machine. I sold it because I don't do imaging and it was mostly sitting in the back of my garage gathering dust; I replaced it with a Dobsonian mount, more fitting with my style of visual observing.
2007-11-23 09:42:14
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answer #4
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answered by GeoffG 7
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Well, this is a pretty difficult quesiton- and lets face it, the pictures here sux!
Why not take your light bucket and the rig you have, and take it to the local astronomy club and ask some of the senior memebers how they'd improve your system?
I bet they could fix you right up, for a heck of a lot less than 5 grand- good luck
2007-11-23 00:04:44
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answer #5
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answered by Anonymous
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I only dip my toes into this side of Astronomy so I can't help personally.
But I know where some of the best amateur and semi professional Astrophotographers in the southern hemisphere hang out.
www.iceinspace.com.au It's free to join.
They would be more than happy to help you out with your problem. Nice people, very friendly and generous with their knowledge.
Cheers
2007-11-23 07:04:36
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answer #6
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answered by Anonymous
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