Re: [Utah-astronomy] Current ATM Project
Thanks Don. That is good advice. I came to that conclusion a few days ago. I have already ordered an off-axis guider that is custom machined to fit between the 3" Wynne corrector and the FLI filter wheel and camera. Guiding through the main scope should solve all my flexure problems. I had to order it from Europe, and it could take 5 weeks plus shipping time... BUMMER! Cheers, Tyler Sent from my Verizon Wireless 4G LTE DROID "Don J. Colton" <djcolton@piol.com> wrote:
Tyler wrote:
"I am still struggling to get my new astrograph up and running perfectly. I have produced a few decent images, but I am having flexure issues and can only get 1 minute exposures right now. I disassembled the entire unit today, trying to troubleshoot. I may be coming to the next ATM session for a little guidance and advice, along with some liver and onions."
I had the same problem at longer focal lengths 2,300 mm using a guide scope with my Mewlon. However with the new SBIG STT camera with built in off axis guider on the filter wheel in front of the filters all of the guiding problems disappeared. Using an off axis guider of some sort might be easier than fixing flexure issues.
Clear Skies,
Don
-----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of Tyler Allred Sent: Tuesday, February 12, 2013 5:31 PM To: 'Utah Astronomy' Subject: Re: [Utah-astronomy] Current ATM Project
Chuck, I would guess that you could do some nice imaging with that scope. I really enjoyed my Takahashi Sky 90 (F/5.6), which was a fast doublet, but not quite as fast as yours. I used it for some really nice images. The Tak had a little bit of blue halo on the bright stuff, but overall it was a very good performer for most objects.
The coma corrector will almost certainly be needed with such a fast achromat, but that may depend on the size of your camera chip. I am guessing that the color correction may not be too big of an issue. You could always go with a monochrome camera and filters, which would also help a bit over a one-shot color chip.
I am still struggling to get my new astrograph up and running perfectly. I have produced a few decent images, but I am having flexure issues and can only get 1 minute exposures right now. I disassembled the entire unit today, trying to troubleshoot. I may be coming to the next ATM session for a little guidance and advice, along with some liver and onions. :)
Some of my favorite images are the wide field stuff. That scope could be a lot of fun. Cheers, Tyler
-----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of Chuck Hards Sent: Tuesday, February 12, 2013 3:21 PM To: Utah Astronomy Subject: Re: [Utah-astronomy] Current ATM Project
Thanks Tyler!
What do you think about using the RFT for imaging? I'm pretty sure I'll need to use my coma corrector, but I'm not sure about the uncorrected color of an achromat on a CMOS or CCD chip. It won't be an issue with narrowband imaging of course, but what about with a color camera? Would a V-block filter do any good? It would probably only be a problem with objects emitting a broad spectrum such as galaxies and star clusters. Emission nebulae won't pose any difficulties.
I've used short-focus doublet refractors for astrophotography in the past, but that was emulsion photography, not digital imaging.
That wide field is just begging me to try it.
On Tue, Feb 12, 2013 at 3:09 PM, Tyler Allred <tyler@allred-astro.com>wrote:
That looks awesome Chuck! Tyler
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Back when I was doing emulsion astrophotography, I encountered flexure problems as well. I eventually traced it to plastic guidescope adjustment screws that were too long (rings too large) but also cured it with a Lumicon 2" off-axis guider. On Feb 16, 2013 11:18 PM, "Tyler Allred" <tyler@allred-astro.com> wrote:
Thanks Don. That is good advice. I came to that conclusion a few days ago. I have already ordered an off-axis guider that is custom machined to fit between the 3" Wynne corrector and the FLI filter wheel and camera. Guiding through the main scope should solve all my flexure problems. I had to order it from Europe, and it could take 5 weeks plus shipping time... BUMMER! Cheers, Tyler
Sent from my Verizon Wireless 4G LTE DROID
"Don J. Colton" <djcolton@piol.com> wrote:
Tyler wrote:
"I am still struggling to get my new astrograph up and running perfectly. I have produced a few decent images, but I am having flexure issues and can only get 1 minute exposures right now. I disassembled the entire unit today, trying to troubleshoot. I may be coming to the next ATM session for a little guidance and advice, along with some liver and onions."
I had the same problem at longer focal lengths 2,300 mm using a guide scope with my Mewlon. However with the new SBIG STT camera with built in off axis guider on the filter wheel in front of the filters all of the guiding problems disappeared. Using an off axis guider of some sort might be easier than fixing flexure issues.
Clear Skies,
Don
-----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of Tyler Allred Sent: Tuesday, February 12, 2013 5:31 PM To: 'Utah Astronomy' Subject: Re: [Utah-astronomy] Current ATM Project
Chuck, I would guess that you could do some nice imaging with that scope. I really enjoyed my Takahashi Sky 90 (F/5.6), which was a fast doublet, but not quite as fast as yours. I used it for some really nice images. The Tak had a little bit of blue halo on the bright stuff, but overall it was a very good performer for most objects.
The coma corrector will almost certainly be needed with such a fast achromat, but that may depend on the size of your camera chip. I am guessing that the color correction may not be too big of an issue. You could always go with a monochrome camera and filters, which would also help a bit over a one-shot color chip.
I am still struggling to get my new astrograph up and running perfectly. I have produced a few decent images, but I am having flexure issues and can only get 1 minute exposures right now. I disassembled the entire unit today, trying to troubleshoot. I may be coming to the next ATM session for a little guidance and advice, along with some liver and onions. :)
Some of my favorite images are the wide field stuff. That scope could be a lot of fun. Cheers, Tyler
-----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of Chuck Hards Sent: Tuesday, February 12, 2013 3:21 PM To: Utah Astronomy Subject: Re: [Utah-astronomy] Current ATM Project
Thanks Tyler!
What do you think about using the RFT for imaging? I'm pretty sure I'll need to use my coma corrector, but I'm not sure about the uncorrected color of an achromat on a CMOS or CCD chip. It won't be an issue with narrowband imaging of course, but what about with a color camera? Would a V-block filter do any good? It would probably only be a problem with objects emitting a broad spectrum such as galaxies and star clusters. Emission nebulae won't pose any difficulties.
I've used short-focus doublet refractors for astrophotography in the past, but that was emulsion photography, not digital imaging.
That wide field is just begging me to try it.
On Tue, Feb 12, 2013 at 3:09 PM, Tyler Allred <tyler@allred-astro.com wrote:
That looks awesome Chuck! Tyler
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Well, the RFT is about done, down to just some tweaks and adjustments before she's ready for first light. I got the tube flocking installed late last week and put it all together. I still need to give the objective a thorough cleaning before final assembly. Here it is, all painted, assembled, and with the accessory bridge plate attached to the top of the tube rings. Note that I mounted it off-center, mostly to give my head more room next to the main tube, since my right eye is dominant and the one I use when using straight-through finders. It also gives me more room under the plate should I choose to use a hand knob to attach accessories instead of a machine screw. 55mm home-made finder in the foreground. http://i260.photobucket.com/albums/ii24/JethroTull1958/ATM/110mm001_zps67b00... Here's a close-up of the accessory/bridge plate. 1/4" thick aluminum, with a 1/4" wide slot machined lengthwise (done with an ordinary router and carbide bit). The bottom of the slot has a 1/2" wide recess 1/8" deep running it's length, like commercial dovetail plates, to accomodate a washer under the screw head. Note the off-center position. I may change this to a centered position if I find drawbacks in practice (balance maybe). http://i260.photobucket.com/albums/ii24/JethroTull1958/ATM/110mm002_zps2f5e9... This shot shows my 50mm f/9 spotter (home-made from a surplus objective) mounted on the accessory plate, but any small scope, camera, or reflex sight can be mounted there. http://i260.photobucket.com/albums/ii24/JethroTull1958/ATM/110mm003_zps665e9... The completion of this scope pretty much guarantees bad weather for a week or so. Sorry folks! ;-)
participants (2)
-
Chuck Hards -
Tyler Allred