M8 M20 Redo with PixInsight

As many astrophotographers used PixInsight and drawn my attention for sometime. But for a slow learner and slow respondent like me, I needed to wait until the end of academic year! Anyway, I found that PixInsight is something like PhotoShop, which is huge in functions and the learning curve is long. This is my first piece of PI work. I used Registration, Dynamic Background Extraction, Background Neutralization and Color Calibration etc. In handling this image, I found that Background Neutralization is particularly useful! The result is simply great and make the final touch with Photoshop much more easy! I also attached a comparison between PI & DSS. The DSS version was processed a week ago.

A good partner of APM-TMB 105-650: Borg 7704 Super ED Reducer

A long waited Borg 7704 Super ED reducer first light. It is a discontinuous model and I bid it from a Japan website http://www.buyee.jp/. It turns out that 7704 works perfectly with my APM-TMB 105/650. Although the back focus of Borg 7704 was not fine-tuned and default value was used, the stars at the extreme corners were reasonably sharp. There was more distortion at the lower left corner. It takes me sometimes to tune it anyway.

Date: 15-16/6/2015

Location: Pak Tam Chung, Hong Kong

APM-TMB 105/650 with Borg 7704 @F3.9, AVX, D1, 5DII, MGEN II

M8 + M20 : ISO 1600, 3mins x 25, Dark, Flat, Bias, uncropped

M16 + M17: ISO 1600, 3mins x 9, Dark, Flat, Bias, uncropped

North American Nebula: 9-7-2012 Pak Tam Chung

I went o Pak Tam Chung (北潭涌) this Monday and captured the North American Nebula. To me it is just a practice & I used two flatteners to image the North American Nebula, namely WO FLT (zero power) & the APM Riccardi Super ED reducer (0.75X). After finished the imaging with Riccardi reducer, clouds covered!!! I only got one frame of North American Nebula with the FLT flattener. So I just post the resized raw image.

For the combo of APM-TMB 105/650 & APM Riccardi Super ED 0.75X reducer

APM-TMB 105/650, APM Riccardi Super ED reducer, P2, HEQ5Pro, LVI II, 5DII (Astrodon Modified)

ISO 1600, 16 x @2mins, Dark Frame, Flat Field

DSS, PS

For the combo of APM-TMB 105/650, WO FLT flattener

APM-TMB 105/650, WO FLT flattener, P2, HEQ5Pro, LVI II, 5DII (Astrodon Modified)

Since I only got 1 frame, so just resized unprocessed photo

APM-TMB 105/650, Riccardi 0.75X

APM-TMB 105/650, FLT, resized unprocessed raw

6-6-2012 Venus Transit

After the disappointing annular eclipse in Hong Kong, finally we got a successful Venus transit in 6-6-2012! I led my students to the observation site, somewhere between Clear Water Bay (清水灣) and Po Toi O (布袋澳) at about 4:30am in the morning. We setup the equipment quick and waited the sunrise. As the transit would start short after the sunrise, we got limited time to get focusing and exposure setting ready.

As expected the angle of elevation was low, clouds ran around and the images on the notebook screen were very dim. We were anxious about couldn’t catch the important moment, the first contact. Luckily, we just made it before the transit! The imaging was successful, although some images were affected by the sky condition.

        In the past 3 weeks, I tried my best to rectify the images in terms of details, color tune and brightness. The most difficult part was the beginning of the Venus transit. It was because of the clouds. The alignment point of Registax just failed in tracking. I needed to reject those bad frames manually and tried to use different alignment points in order to get the best possible results. Anyway, I finally created this 150M pixels image! (10,000x15,000 = 150,000,000 pixels) See you 105 years later!

M45 Pleiades: A trial shot

This M45, Pleiades (七姊妹星團) was taken with an APM-TMB 105/650 with WO’s FLT flattener in 24-11-2011 at Pak Tam Chung, Hong Kong. I didn’t optimize the back focus for the flattener in present of P2 filter. The performance was good. I need to wait for clear skies to do the optimization, but the sky in HK is always disappointing. Maybe I need to use artificial star to do the optimization. Although the distance is not infinity, it gives an approximated back focus adjustment. This can save me some time during field test.

APM-TMB 105/650, FLT, P2, Canon 5DII, HEQ5Pro

ISO 1600, 5 mins x 10

DSS, PS4, cropped

10-12-2011 Total Lunar Eclipse at Hong Kong

What a wonderful lunar eclipse! This is the first time I imaged the whole total lunar eclipse. I was so luckily that the weather was exceptionally good in Hong Kong. I enjoyed the total lunar eclipse for about six hours! However, due to lack of experience, my photos were not good. I did every in rush. Now after reflection I summarized the reason of these bad photos.

1. I pointed the scope to Jupiter and got it focused with the focusing mask. It is no good to use planets to do focus. They are extended objects, the diffraction spikes are wide. It is hard to make judgment whether it is in focus. It is by all mean pick a bright star to do focusing.

2. My scope was placed inside my car’s boot for an afternoon. I guess the temperature is around 20oC to 23oC that day. However, the average temperature while I took the photos is about 14oC and the lowest temperature was 11oC. I checked the focus at the end of the eclipse by pointing the scope to Sirius. It was out of focus! According to previous testing, the focal shift was about 6x7=42um (6 divisions in electric Feather Touch focuser and each division is about 7um displacement). So I should check the focus regularly, say every 30 mins.

3. During the whole lunar eclipse, the brightness of the moon varies a lot. In my case, I set the ISO to 800, the corresponding shutter speed varies from 1/4000s to 1/10s. In addition, I need to pick different exposures for selections later. Originally I set the interval of the programmable shutter to 1 min. I noticed that I need more exposure for selection in the middle of the imaging. It is luckily that I can still make it by doing bracketing exposures for every time intervals. So it is quite an involving job!

4. The shutter speed would be slow at totality, if the ISO is not high enough. In my case of ISO 800, the shutter speed was down to 1/10s. For tele-photography, one should use high ISO. So get a low noise camera and set high ISO.

My first successful solar mosaic!

I tried several times, but failed. This is the first time, the image looks decent.
LS80T, DMK21, EQ3Pro, mosaic of 6 panes