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Old 07-06-2021, 04:16 PM
tornado33
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My deepest Antennae, and others.

last evening say chilly temperatures and an unusually good night sky. The Antennae Galaxies were well placed for observing. I positioned the scope for observing west of the meridian, moved it as far east till the tube end rested against the pier, somewhat east of the meridian then waited till the object moved into view, turned on the drive, framed it to fit in NGC 4027 as well, then started.

Did a small pic with the 2 main objects right together.

Full size here https://www.astrobin.com/nm42v2/?nc=user

The EOS Ra is so good for framing, short 5 sec shots at high ISO easily show the two galaxies, was a matter of rotating the frame to fit them in, happily a good guidestar was also in view of the guide cam.

11 x 15 mins ISO 400. 10 inch f5.6 newtonian. I was amazed to see the subs still quite dark. Did 11 before I started nodding off (Id ran in and come 3rd overall in the Maitland River Run Half Marathon that morning, so had been a big day, happy to cap it off with some astroimaging.

Must better shots about but Im really happy to pull this off from such a suburban location where transparency and seeing are usually ordinary at best, and with a 1986 vintage telescope and mount. All hand guided. So nice to see a small stable guidestar too.

Still had issues with gradients which make themselves known when pushing to bring out faint stuff. Not perfect could probably tweak it some more.
calibrated in IRIS finished off in Photoshop
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Old 07-06-2021, 04:25 PM
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multiweb (Marc)
ze frogginator

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Fantastic details. One of the best antennae on these forums
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Old 07-06-2021, 04:34 PM
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strongmanmike (Michael)
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Excellent image Scott and nicely framed, well done

Long live the Samson mount!

Mike
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Old 07-06-2021, 07:57 PM
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PKay (Peter)
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I immediately give 10 / 10 for someone who guides by hand esp. after running a marathon

Being 'new school', I still don't know what it means, do you push the scope around?

Great effort Scott
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Old 07-06-2021, 08:34 PM
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Atmos (Colin)
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Very nice!
You definitely weren't shaky at all after the marathon
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Old 07-06-2021, 10:06 PM
tornado33
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Thanks so much everyone.
The Sampson Mount uses a 50 Hz synchronous motor that drives the RA axis at around sidereal rate. It runs through a drive corrector with a hand control with Fast and Slow buttons that either speed the motor to about 70 Hz or slow to 30 Hz on a hand control. There's also a fine speed control knob on the hand control.

The guide star is highly magnified. See pic. Each square is a pixel and at 1400mm fl would be about an arc sec maybe less.

As soon as I see the star drifting in RA I use the fast or slow buttons to keep it centred. Drift in DEC is very slow and doesn't need much correction by means of old fashioned slow motion hand control because Sharpcap gets me so well polar aligned. See next pic.

The Sampson drive is quite predictable in its periodic error. Each time the worm takes up another tooth it will speed up and slow down or vice versa. I use the fine speed control knob to match this as best I can then make quick presses on fast or slow buttons to keep that guide star right on that reticle.

Yes the drawback is i cannot leave while the scope is imaging. I have to be there watching the screen to make those constant corrections. But I can have music on, or have TV in a window on the laptop. On a weekend it's often the footy! On one Friday night I even participated in a zoom meeting with our Newcastle astronomical society while I imaged! Multitasking at its finest haha

Its rare i have to throw out a sub unless its a bit windy. I always balance the scope slightly east heavy so its constantly meshing against the worm wheel to avoid backlash. All 11 subs in last night's session were kept.

Its fun extracting what I can get out of this ancient system. I still think I have it easier than the bad old days of hypersensitised film and single exposures that had to run an hour or more, and not know it worked till it was developed
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Old 08-06-2021, 08:20 AM
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PKay (Peter)
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You so have to work out PHD Scott.

I could actually play footy whilst imaging, if it wasn't dark

However most enlightening and thankyou.

Have to hand it those who guide by hand, now I know what it means...
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Old 08-06-2021, 04:40 PM
tornado33
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I guess if a Dec drive could be fitted and that wired so that it and the RA drive corrector could be controlled by PHD then autoguiding could be possible with the ancient Sampson mount. Would be a lot of work. For now its hand guiding. With the accurate polar alignment perhaps I could autoguide without making dec corrections.
A great thing would be one of those adaptive optics things that can do fast corrections and I could guide more relaxed
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Old 09-06-2021, 12:20 PM
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Retrograde (Pete)
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Producing such an image with hand guiding - whoah!

I still remember hand-guiding on Comet Halley back in the day, peering at it through an illuminated reticle eyepiece for over an hour on a single exposure. Of course I was young and flexible - these days I'd need two weeks of intensive physio just to recover!

Last edited by Retrograde; 09-06-2021 at 09:59 PM. Reason: Clarity
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Old 09-06-2021, 02:09 PM
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cometcatcher (Kevin)
<--- Comet Hale-Bopp

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Wonderful image Scott! Long live the Samson mount! I wish mine was computerised. It's got beefy shafts, unlike my puny SW NEQ6.
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Old 09-06-2021, 09:28 PM
Alchemy (Clive)
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If it ainít broke donít fix itÖ..😎

However I think itís warmer in Newcastle than down here in southern Victoria, too cold for me to sit outside all night, although I do have to pop out regularly to check focus, as I donít have autofocusÖ.. Iím thinking you donít have an issue there either as you check each sub as it downloads
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Old 16-06-2021, 10:20 PM
tornado33
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Many thanks. The camera downloads each sub to the laptop as soon as it is taken so I can briefly check it if I need to but I can usually tell if it will be good or not by the guiding, I can usually get the guidestar to sit right on the virtual reticle to the limit of the seeing.

I have the image very highly magnified so each pixel is a few mm across on the screen and usually have a star bright enough for exposure times of less then 100 milliseconds with the ZWO guide cam. If it is windy though the guidestar bounces around so I really need fairly calm nights to image
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