My astrophotography 2021

[hhzhang]

In the pre-dawn hours, the milkyway core has risen high in the sky. The milkyway season has begun.

[Airconvent]

Nice capture! ....the Milkway is coming back but I think the gas giants will not be ideally positioned for another few months.

[hhzhang]

2021-3-11 dawn time. A quick shot before sending kids to school.

Apparently I need to find a better foreground for similar targets.

[hhzhang]

2021-3-15

The Crux-Eta-Carina region



Practice shooting 50mmAPSC FOV skies. Hope one day can shoot from a truly dark site this year.

[hhzhang]

Also attempted at very wide-angle photography. The idea was to capture the rich southern region of the Milky Way: due to their low altitude even at meridian, these stars are a bit unfamilair to me -- except for the Alpha-Beta Cen, the southern cross, and the fake cross.

The outcome turns out better than expected. Many objects show up. Can you identify e.g. the omega centauri cluster?

But the light pollution from the vessels in the strait is way too much to remove -- otherwise (if helped by clearer skies perhaps) the milkyway shape could be seen -- I believe.

Another lesson learnt is that I should have avoided shooting from behind the array of barrier bars -- they (together with the distance light sources) created uneven and regular patterns in the images -- meaning I could not stretch further that was however necessary for uncovering fainter details.

[hhzhang]

The young waxing crescent moon. 2nd cycle (month) for the year of Ox.

[celeron787]

Also attempted at very wide-angle photography. The idea was to capture the rich southern region of the Milky Way: due to their low altitude even at meridian, these stars are a bit unfamilair to me -- except for the Alpha-Beta Cen, the southern cross, and the fake cross.

The outcome turns out better than expected. Many objects show up. Can you identify e.g. the omega centauri cluster?

But the light pollution from the vessels in the strait is way too much to remove -- otherwise (if helped by clearer skies perhaps) the milkyway shape could be seen -- I believe.

Another lesson learnt is that I should have avoided shooting from behind the array of barrier bars -- they (together with the distance light sources) created uneven and regular patterns in the images -- meaning I could not stretch further that was however necessary for uncovering fainter details.

Love the widefield! Many many objects too. Isn't the asi2600 just released recently? I just got my guiding setup and have been playing around with phd2 drift alignment and guiding. Haven been able to nail it down right. Any tips?

[hhzhang]

Love the widefield! Many many objects too. Isn't the asi2600 just released recently? I just got my guiding setup and have been playing around with phd2 drift alignment and guiding. Haven been able to nail it down right. Any tips?

Thanks! Admit it is a pain shooting wide field astrophotographs with a landscape/seascape? foreground in Singapore. The ships off the east coast go brighter and brighter in their use of lights. Would they shift to different anchor places once the Tuas mega port is fully operational? I hope so! Give the dark skies back to us please!

My camera is the one-color-shot version (ASI2600MC Pro) which came out 1+ year ago. The new black-white version (ASI2600MM Pro) was just released a couple of months back.

What specific problem have you encountered using PHD2 autoguiding on the tracker?

On the tracker, you need to first turn off the PHD2 autoguiding on DEC. Then if the calibration goes well, the drift alignment and guiding will be quite smooth.

[celeron787]

Thanks! Mine is the one-color-shot version which came out 1+ year ago.

What specific problem have you encountered using PHD2 autoguiding on the tracker?

On the tracker, you need to first turn off the PHD2 autoguiding on DEC. Then if the calibration goes well, the drift alignment and guiding will be quite smooth.

So my process is: Do DARV (I find pointing north puts me way far off), point scope straight up for azimuth correction, calibrate, adjust dials until line relatively straight (best polar alignment error I got is about 3). Then loosen RA clutch and point scope towards East horizon (lowest I can go is about 20 degrees), recalibrate, adjust altitude knob till line relatively straight (best I got is 5). If I move the scope back to overhead, I find that azimuth alignment is out after adjusting altitude, so I redo it.
Tests shots after that at 30sec still shows very slight trailing with guiding. I was wondering is it a matter of practice or am I doing something wrong? I can spend about 2hrs doing all the fine adjustment, is there a shorter way to do it?

[hhzhang]

Thanks! Mine is the one-color-shot version which came out 1+ year ago.

What specific problem have you encountered using PHD2 autoguiding on the tracker?

On the tracker, you need to first turn off the PHD2 autoguiding on DEC. Then if the calibration goes well, the drift alignment and guiding will be quite smooth.

So my process is: Do DARV (I find pointing north puts me way far off), point scope straight up for azimuth correction, calibrate, adjust dials until line relatively straight (best polar alignment error I got is about 3). Then loosen RA clutch and point scope towards East horizon (lowest I can go is about 20 degrees), recalibrate, adjust altitude knob till line relatively straight (best I got is 5). If I move the scope back to overhead, I find that azimuth alignment is out after adjusting altitude, so I redo it.
Tests shots after that at 30sec still shows very slight trailing with guiding. I was wondering is it a matter of practice or am I doing something wrong? I can spend about 2hrs doing all the fine adjustment, is there a shorter way to do it?

Is the trailing (with autoguiding on) in the DEC or RA? I guess it is DEC. From what you describe, you have already achieved a very low alignment error (suppose the unit is arcmin).

The visibility of a given DEC/RA error is determined by your pixel scale. If my total drift error RMS is 2.x'' per minute (not difficult), I would then start shooting 1-min subs with ~200mm FL + 3.76micro pixel size (~4"/px). This can be relaxed a little bit in my practices.

Sometimes I feel the alignment may not hold position once you slew to different positions. And the trialing effect would different for the same error but at different positions. So sometimes I just point the scope/cam to the target object and do a quick PHD2 drift alignment there to ensure the error is controlled.

I think the alignment work for the above target performance should not exceed 10 minutes.