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INDI Library v1.8.5 Released (19 Apr 2020)

April 2020 release of INDI Library v1.8.5 introduces new drivers while providing fixes and improvements to existing devices and core framework.

Off axis guider settings ?

1 year 1 month ago
CAS
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Off axis guider settings ? #37712
Hi,
stupid question of the week coming........

Kstars asks for the focal length and aperture of the guide camera. I intend to use an oag. Therefore, should I tell it my scope details or camera. ?

(I can almost hear the howls of laughter and derision)

Thanks in advance,

cas

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1 year 1 month ago
wvreeven
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Off axis guider settings ? #37719
No laughter or howling from me. What "focal length and aperture" does the camera have? You need to enter the scope details and of course the pixel size and amounts of the camera.

Clear skies, Wouter

ASI1600MM-Pro Cooled and filter wheel with a SkyWatcher Esprit 80 ED on a SkyWatcher HEQ5-Pro
ASI1600MM-Pro Cooled and filter wheel with an 8" TS Ritchey-Chrétien on a SkyWatcher EQ6-R
The following user(s) said Thank You CygnusX1

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1 year 1 month ago
CAS
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Off axis guider settings ? #37721
Hello, thanks for your reply.

The camera is a zwo asi290mm mini. Pixel size is 2.9 microns. There is nothing listed for fl or fr, only its back focus, this is 12.5 mm

Regards,

cas

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1 year 1 month ago
wvreeven
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Off axis guider settings ? #37723
Hi Cas,

In case of ZWO cameras Ekos gets the pixel info from the camera itself so that's why you don't need to specify that.


Clear skies, Wouter

ASI1600MM-Pro Cooled and filter wheel with a SkyWatcher Esprit 80 ED on a SkyWatcher HEQ5-Pro
ASI1600MM-Pro Cooled and filter wheel with an 8" TS Ritchey-Chrétien on a SkyWatcher EQ6-R
The following user(s) said Thank You CAS

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1 year 1 month ago
CAS
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Off axis guider settings ? #37724
Great,

thanks very much

Clear skies,

cas

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1 year 1 month ago
Ron Kramer
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Off axis guider settings ? #37763
I Read the above - you didn't really get your answer did you. = )

In most cases if wants the guiding scope info. For a guide scope (see their specs) often 50mm and maybe 240mm.
With a OAG you need to enter your primary scopes specs.

When I use a OAG. (which is most of the time). When I'm setting up my 80mm. I enter the focal length for the scope (480mm) in the stellarvue specs. It's aperture is 80mm. (size of the objective).
If I use a field flattener (usually) it's the 480mm x .8 (.08 FF) so that makes it a 384mm aperture 80mm.

When I use my 6" APO it has a .75 FF. So it's a 1216mm scope. AP is 152mm. (6") with the FF it's 1216 x .75 so I enter 912mm FL and 152mm AP. (aperture). size of the primary for light gathering.

If will often ask for pixel size and often the width and height of the guide cameras sensor. Find that in the specs for your camera.

So to answer your question - enter the FL and objective mm of the primary telescope which is (WITH A OAG) also your guide scope.

OAG's are great - I have 3. I like to leave them on each scope as a single unit to swap out. The hardest part is adjusting the depth of the prism into the FOV and not allow it to cast it's shadow on the primary cameras sensor. If you pull it out to far you will get distorted stars on the fringe of the projected image. So better to get in INTO the projection area to get a nice sharp star.... but not so far in that it leaves a shadow on the primary image. A little balance is called for. Then the distance of the guide camera has to be the same distance as the main camera... because they both need to be set to focus at the SAME POINT from the primary scopes focuser. Focus the telescope and primary camera first. Once in focus slide the guide camera up and down (to change distance) while looping the view and find the spacing with the best focus. Lock it down with the set screw(s) and then when you focus the primary image the guide image will also be in focus. Sometimes this will take extra extension tubes to find the proper focus distance. Once set - forget about it!

I never fear asking a dumb question because after someone answers it, I'm not as dumb as before I asked! = )
Couple pics attached if two different scopes with my OAG's.

AP Mach1 / CP4 APCC & PEMpro.
EXP SCI - ED152cf APO - Celestron 11" RASA - Stellarvue 80mm
Baader F2 HS NB filters, Lodestar X2 guide camera / OAG - ZWO 290mm mini
ZWO ASI1600MM Pro / ASI174M (solar) / ASI094MC
NEXDome, CLoudwatcher, AVX mount/ASIair and Stellarmate

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1 year 1 month ago
Ron Kramer
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Off axis guider settings ? #37764
Rather than ask stupid questions I like to do stupid things... it's called Learning the hard way. = )


AP Mach1 / CP4 APCC & PEMpro.
EXP SCI - ED152cf APO - Celestron 11" RASA - Stellarvue 80mm
Baader F2 HS NB filters, Lodestar X2 guide camera / OAG - ZWO 290mm mini
ZWO ASI1600MM Pro / ASI174M (solar) / ASI094MC
NEXDome, CLoudwatcher, AVX mount/ASIair and Stellarmate

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1 year 1 month ago
CAS
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Off axis guider settings ? #37767
Hi Ron,

thanks for your extended answer.

I think(or the way I took it anyway )wvreeven's second sentence was what he was getting at. You've confirmed that for me, thanks :)

Did you REALLY set up Hyperstar like that ??????

Thanks,

cas

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1 year 1 month ago
CAS
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Off axis guider settings ? #37768
Third, rather :)

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1 year 1 month ago
wvreeven
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Off axis guider settings ? #37770
Yeah Ron has a rather lengthy way of confirming what I wrote in that third sentence :whistle:


Clear skies, Wouter

ASI1600MM-Pro Cooled and filter wheel with a SkyWatcher Esprit 80 ED on a SkyWatcher HEQ5-Pro
ASI1600MM-Pro Cooled and filter wheel with an 8" TS Ritchey-Chrétien on a SkyWatcher EQ6-R

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1 year 1 month ago
ChrisRowland
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Off axis guider settings ? #37771
It's the sofa mount I like :) Guide corrections by moving a small weight across the cushions.
Perhaps Ron has his house on an equatorial mount. Hope it's a fork mount, a pier flip doesn't bear thinking of.

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1 year 1 month ago 1 year 1 month ago by Ron Kramer.
Ron Kramer
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Off axis guider settings ? #37772
I'm old and retired - what else do I have to do. Plus after 72F last weekend - there is a snow blizzard thing going on out there today.
(white out)

YES I did that - it's a RASA (similar to a hyperstar). And YES it worked... I ordered the mini guide camera and hoped it would tuck down in behind the EFW.
to my disappointment the focus point had the camera extended "to far out" for my initial concept. (instead of being behind the EFW).

I removed the OAG and went back to an external guide scope for guiding. But the EFW is still installed. = ) The problem was the SPIKE from the hard line of the guide camera.

When people fear posting a dumb question, a vague response will often puzzle them and surely they won't ask again. I wanted to be sure you received a helpful welcoming answer.

AP Mach1 / CP4 APCC & PEMpro.
EXP SCI - ED152cf APO - Celestron 11" RASA - Stellarvue 80mm
Baader F2 HS NB filters, Lodestar X2 guide camera / OAG - ZWO 290mm mini
ZWO ASI1600MM Pro / ASI174M (solar) / ASI094MC
NEXDome, CLoudwatcher, AVX mount/ASIair and Stellarmate

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