Saturday, April 30, 2005

Saw that active sunspot today

First time to use H-alpha with a suitable adapter, image quality MUCH improved probably due to collimation... saw that active sunspot for several seconds (!!) and impressed!!!

Sunday, April 24, 2005

23/24 April

Forgot to write yesterday night. Jupiter came close to the moon last night, not bad, did some capture but poor planning again. I should have done two separate exposure to capture lunar disc detail and jovian sat... anyway... did a cheap webcam 4 image mosaic but poor result, also a high power ranger jup.

today, woke up and wait for shooting... transparency was high but within 10 minutes, all gone wrong, cloudy..~!!! could even see the moon... maybe God asked me to sleep earlier today... oh... I just want one/two clips... while waiting for the jup to clear my window... die....

Friday, April 22, 2005

A short (long) session

Woke up at around 1:00am, and started some lunar imaging at f/10 using C8. Transparency was so poor that even f/20 will need 100% gain. So, forced to conduct a low power game. Some nice sights were captured.

Later tried on Jupiter, no chance to collimate on any star, and I used one of the Jovian satellite to check collimation, seems not bad. Anyway. At f/20, the detail level is even less than f/10 due to overwhleming noise.

But someone else managed to get f/30 shots... how come?! shall really investigate.

Wednesday, April 20, 2005

H-alpha exposure

I've been exploring last two days, my wife has just delivered our baby and I'm spending time with them, and I managed to get sometimes with my scope when they're sleeping in the afternoon.

Back to my queston, I used a webcam, a Ranger, SM40 with BF10.

I found that prominence and surface detail requires very different exposure setting.

I found that, surface detail reveals itself at the lowest exposure among all the h-alpha details, the correct range is very narrow and the image on the display will be red (normal) and it's quite hard to see it bright day light even I cover myself... maybe my eyes are too weak on red...

on pushing up the exposure, surface detail will be washed out and prominence will come into the view. Again, the correct exposure range is quite narrow, or else you saturate the brightest part very easily.

the funny thing is, if I further push up the exposure, the surface detail will re-appear, but this time, it's in orange but not red.

H-alpha should be red, I was puzzled and I spent time to think of it... why is that?

My preliminary thought is that, due to the high exposure setting, h-alpha signal got sneak into the G and B channel of the webcam. At this setting, normal R channel will be saturated, and so with G and B signal, the surface detail re-appeared. Prominence is about right in R channel as well.

Any idea, comment? Thanks...

Thursday, April 07, 2005

Short Jupiter observation

Jupiter comes into my view during mid-night, but I can only observe with with my Ranger. If I am to use the C8, I will have to wait it to sink lower which is not so favorable. Taken two images, one with a IR block and one without. Processing pending for the one without IR-block. Seeing no good, only those standard detail available.

Also had a look on Saturn by using the Unistar Light plus Ranger, since even with the TGSP II, I won't be able to point to it. So, it's a goodbye to Saturn for imaging at home.

Seems like it's a BIG hindrance for me to continue my home imaging except the sun and the moon.

Possible solution is to find a shorter tripod, or to find an alternative way to motorize my Giro mount again, but I dare not to do it all over again. Or maybe buy a smaller OTA? Or just get a small fork mounted computerized scope so that I can push it out from the window?