Wednesday, August 30, 2006

Short imaging session - but 5 targets!

This time tracked by LXD55, again, the results show that, even a small 75mm f/1.8 lens with DMK, reveal far more than I can detect visually with a C8, maybe video astronomy is the way to go for urban indoor astronomy.

Belows are mostly identified after the session, the M8 could be M20? Is that M6 really M6? Only the M17 is really M17... haha...

Target 1 (M25?): 4.524s * 100 medium gain - clip 1

Target 2 (M8): 7.493 * 60 medium gain - clip 2

Target 3 (M6?): 2.732s * 50 medium gain - clip 3

Quick and dirty processing on spot:-

Re-processed, this one was getting very low (just above the buildings in front of me), so the noise is pretty serious:-

Target 4 (??): Unknown target - clip 4

In this session, I scanned around with a 8mm lens, stop when I saw non-stellar faint fuzzy, and then I centered it and use my 75mm lens to zoom in, so I would stop by unknown target, this one is probably a big open cluster or just a star rich region of the milkyway?

Target 5 (M17):

5.132s * 60 medium gain - clip 5

12.409s * 30 low gain - clip 6

Quick and dirty on-spot processing:-

Reprocessed version:-

Finally, here's a M17 combined by the two above:


I found that I can push the exposure time a bit longer, but I was held back by the sky glow, however, the histogram from the stacked images told me that I could go further to gather more signal actually.

These series of images told me that, for urban indoor setting, maximum exposure time (30s only) of the DMK is enough to play with, by going longer the frame is going to white out. However, by using narrow band filters, I guess longer exposure time is needed and it would be far more effective.

For lazy guy like me, this is probably I'd enjoy, however. Very rough polar alignment is what I need, a compass is not even used. :-)

Short fixed tripod scanning

C mount lens, 25mm at first and then 75mm, DMK 31AF03... around Sagitarius... yet to be identified, 2s * ~80.

Additional Remarks on 30 Aug:

It should be M22.

I simply do it this way, use the widest lens (8.5mm), 0.5-1s at nearly maximum gain to scan around until I saw any non-stellar faint fuzzy, then I center it and then attach the 75mm lens, lengthen the exposure to a point so that the stars will remain pinpoint, adjust the gain to get good balance of exposure and noise, start recording an AVI, and then registax with de-rotation (dead slow), done.

Further processed and cropped version:

Saturday, August 26, 2006


Very quick session, last less than 15 minutes from setup to tear down, hazy sky and thus the solar disc has a reddish circular patch of light around:

more images pending:

too hardly processed:-

Thursday, August 17, 2006


WARNING: Please simply do NOT do it, since it's extremely dangerous even if you follow the following exactly and do it correctly.

Some pictures about the setup:-

The C-ERF:

Very roughly put it in a 70mm lens cell:-

Very dirty hack to put the lens cell on my Borg 45ED custom tube using duct tape:-

This is a special observation conducted in my friend's home, we use a 70mm C-ERF and PST etalon, BF10 to make a bigger scope setup, the result is very satisfactory:

Borg 45ED custom made OTA, duct tape hack with 70mm lens with C-ERF in cell, a chain of Borg adapters to make up the length and a BF10.

An image captured by this setup... too bad that the image scale should be pumped up with the larger aperture, but the sun is too low and even blocked after this image:

Sunday, August 06, 2006

Quick solar observation

Cloudy again!

But got some gap, couldn't take any acceptable photograph most likely.

Solar disc was blank, even no prominence.

Switched to visual observation, long time didn't do it. Binoviewing, oh... wait... I saw a nice hedgerow, not too bright or too tall it's there... oh... one more V shape filament, too!

Again, human eye is the best tool... if long exposure is not needed.

(Thin) moving cloud is an enemy, your eyes are your best friend in that case.

Saturday, August 05, 2006

Quick look on the sun

Had a quick look between small cloud gap.

Saw a prominence loop and a blank solar disc, nothing special, cannot manage to take any shoot too.

Tuesday, August 01, 2006

A new page on indoor imaging

Since downsizing, this is the first time I did indoor imaging. The setup is simple, LXD55 with C5.

The first test is C5 at prime focus using DMK 31AF03, on the moon:

Since autostitch accepts JPG only, so the image quality is less than ideal, quite a lot of noise and useful information are removed by the lossy compression and that prevents any further processing. I shall investigate another way to do the mosaic work. For full size:

Another way to do mosaic, purely by PS, but since I'm very cheap in operating it, the result is terrible:

The second test is 2x barlows on moon, poor seeing means, oops:

The third test is C5 on Jupiter, however, seeing was too bad that Jupiter has some random hair, so didn't get any AVI.