20260414 Comet 2025 R3 Hunting

Woke up at around 5:00am without alarm, pulled out the S30.

The sky is getting some twilights, low in the horizon, scanned with my Canon 10x30 IS but not much luck.  I have no star chart but just scan around near the horizon.

The S30 is struggling too.  The first frame was captured when it says horizontal calibration failed.  It was all white, the twilight was there already.  I should reduce the exposure after it settles with its initialisations and autofusing.

Time is running out, no chance to lower the exposure.

Mission failed, temperature close to zero wthout wind.

Call an end at 5:28am, mission failed.

20250413 Testing the reincarnated Canon FD 300mm f2.8

It can reach focus!  Autofocus works perfectly.

The testing target is M81 and M82, 180s exposure unguided, very fine subexposure.  No processing, seems like a big off centre from the vignetting pattern.  Will use PTEG with carbon fibre to print again for a stronger version.

And then switch to M13 for another test shot, 30s subexposure unguided.

M101 for 180s subexposure.

Setup the S30 along at 22:00, starting from M49, but then that part of the sky was not clear enough.  Gven up.

Turned to M84 and M86, will probably spend quite some time tonight on these.

And then M87.

And then M89, M90, M58 within the same frame:

An unexpected night, the forecast was partially covered but it is actually pretty clear.  Well worth to pull out a bigger setup.

20260412 M13 late night

Just back from Manchester and saw a great sky along the way back home.

Setup the S30 and point it at M13 from around 23:33, let see how much photon I could get.  18 minutes finally.

Then M64 for a short period of time, 21 minutes finally:

Well worth to re-visit it later.

Too bad that I don't have chance to test the 300mm f2.8 out tonight!

Transforming the Canon FD 300mm f2.8L into a telegraph with autofocus via JMI NGF-CM plus a ZWO EAF

The first attempt does not work out well, since it's difficult to print the 77mm thread.  

I have tuned the printing parameters for several times but it didn't help much.

Therefore, I design another adapter from ground zero again.  I found the original 77mm ring for the FD mounting mechanism could be reused and here's the prototype:

Some fitting issues, and I did the fitting with a cutter.

It looks great, with the NGF-CM fitted.

The whole model was refined and printed again.  I will use black PETG in the final version and add felt lined black sticked inside.

Three generation of equipments combined: Canon FD lens, JMI focuser and ZWO EAF.

I am so excited, and I hope I can try it out soon.

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Prototypes

Those thinner rings were the attempts of printing 77mm threads.

The bigger blue adapter was the first prototype of the redesigned adapter without the need of 77mm threads.

Summary: 3D printing could not be too precise, they are plastic afterall.  Expansion and contraction, annealing is apparently an issue.  They are pretty strong but to maintain accurate precision and collimation, you will need to redesign the whole thing.  Don't even try to push its precision or strength, try to avoid these.

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20260409 Additional Notes

Set the limit of focuser travel of the NGF-CM with ZWO EAF in my ASIAir last night.

Set the focuser position to the middle of the travel.

Confirmed that it could reach infinity focus with ample of rooms for adjustment, even without touching the NGF-CM.  So autofocus should work, but to be verified with the stars.

20260406 M102 et al

Continue my Messier Marathon with suboptimal sky.

Started at 9:23pm, summer time marks the beginning of less imaging time.

First up is M102, 28 minutes of exposure:

Next up is M105 with M95 and M96 (mosaic), will do at least one hour of exposure, finally 65 minutes of exposure:

Below will be left for the next time: M103, M85, M64.

Also setup my Canon 200mm f2.8 with guiding Markarian's Chain, containing M84, M86, and surrounding objects, etc.  

No polar alignment was done, just very rough focusing since my ipad air was dead.  Not really easy to do all these with a small mobile screen.  

Try to stack 30s exposures like the S30 therefore.

Very poor result.

Second attempt, reduce exposure to 10s and then stack.

20260405 M109 and Messier Marathon

The quest continue...

Started at 21:42 rather late but it cleared up a bit after the storm dave.

I will send the whole observation session with it, maybe around 45 minutes.  A promising target which deserves better treatment.

Finally, 1:7:30.

20260329 Clear with showers, occassional stormy

Started at around 9:33p (summer time started)

First target is M44 which is pretty close to the moon, but open clusters should be fine.  

6.5 minutes exposure

M63 for 12.5 minutes

M94 for 16 minutes:

M3 for 18 minutes.

Stopped eventually due to shower.

20260328 Messier marathon session three: thin Cloud Observation

Start at around 9:50pm.

M101 is the first target, I have very limited time tonight but I don't want to rush like the last time.  So I am spending more time on this target, 47.5 minutes.

M106 is the next and the last target, see if 10-15 minutes would be good enough.  Stopped at 13 minutes, time to sleep, there's one less hour tonight due to switching to summer time.