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Posts Made By: Ivan Ong

November 9, 2004 03:45 PM Forum: Deep Sky Observing

C9.25"- pretty nice scope!

Posted By Ivan Ong
I went out Sunday night and took my C9.25" observing. I had spent mose summer taking photos with my 4" refractor, so it was nice to do some visual observing for a change. The C9.25" is a nice scope. Once cooled down, it has a refractor-like quality. I turned to the trapezium of Orion and was at first a little astonished I could not see the E and F stars, not even with a 5mm Ortho! Then I colimated the scope and it was night and day, there they were..E and F seen easily, without any effort seen in my 24mm Televue WF. The delicate beautiful of these stars contrasted with their four brighter Trapezium sisters. Folks, this is a great visual scope, very very enjoyable to use. The contrast of the optics, once cooled down, is superb. This scope put away tight double stars easily and also double stars with unequal magnitudes. Using lower power ep's, there is a nice snap to focus that feels like my 4" Tak.
I highly recommend this scope to anyone. I have an XLT
version, and the cost of the OTA is quite reasonable. I have to agree with Ed Ting- the C9.25" is for those who think they hate SCT's!

Clear skies, Ivan

November 15, 2004 01:11 PM Forum: CCD Imaging and Processing/Solar System

M31 from my 20D DSLR.

Posted By Ivan Ong
Last night in the Blue Ridge Parkway was an Astronomer's perfect night. No wind. Clear dark skies. What more can one ask for? Here is a pic of M31 through my Canon 20D coupled to my Tak 4" at f5.9. Litte to no processing at all, just a conversion from the RAW format. I used 5 min at ISO1600 with the auto dark frame feature turned on (CF2=on). What a nice camera!
Ivan

November 18, 2004 08:05 PM Forum: Equipment Talk

Stiletto focuser vs DSLR software

Posted By Ivan Ong
Hi, I'm using a Canon DSLR through the telescope and I was wondering if anyone had difnitive opinions on the merits and accuracy of both these alternative forms of focusing.

Opinions are appreciated. Thanks.
Ivan

November 21, 2004 03:52 AM Forum: CCD Imaging and Processing/Solar System

IR filter neccessary for Webcam?

Posted By Ivan Ong
Quick question: is an IR filter necessary if one is using a ToUCam Pro for planetary photography (set up: C9.5+barlow)

Thanks, Ivan

November 25, 2004 02:12 AM Forum: CCD Imaging and Processing/Solar System

Questions on webcam settings

Posted By Ivan Ong
Hi, a quick question for the experts with Philips ToUCamPro:
I am planning to try my hand with the ToUCam and my Celestron C9.25" and a 2x barlow. I would appreciate it if someone can suggest some initial settings?
-manual exposure?
-10 fps
-brightness?
-gamma?
-saturation?
-is image scale at f/22 ok?

Thanks a bunch! Ivan

November 29, 2004 01:59 PM Forum: Equipment Talk

Celestron CGE: Reasonably Portable?

Posted By Ivan Ong
Hi, for those of you that use this in the field, what is your impression of its portability (set up, tear down ease)? Is it worse than the G-11?
Thanks,
Ivan

December 6, 2004 08:21 PM Forum: CCD Imaging and Processing/Solar System

Combining Images

Posted By Ivan Ong
Hi, I am interested in combining images in MaxIm DL. Say for example, I have three images of the Helix I've taken that I'll like to combine. Which is the algorithm that you will use- sum? average? SD clip? etc. What dictates the choice?

Many thanks for your opinion,
Ivan

December 9, 2004 06:58 PM Forum: CCD Imaging and Processing/Solar System

My first webcam Saturn

Posted By Ivan Ong
Well, I finally took the plunge and purchased a ToUCam Pro and a 3x Televue Barlow and used my C9.25" to image Saturn. Atmosphere was fairly turbulent. Here is a stack of around 600 frames with Registax. Totally nothing close to the experts on Astromart.

What I learned: (a) Need precise collimation on the SCT (b) Need steady air (c) Need very good polar alingment (d) at f/33 guiding and image shift can be tricky.

I am not sure how to improve on this processing. Feel free to try. Many thanks to Mike Sirois for help and hints on the Webcam.

Thanks, Ivan

December 10, 2004 02:11 PM Forum: Equipment Talk

Heat on SCT's: how much is just enough?

Posted By Ivan Ong
Hi All:

I have a 9.25" and I use a Kendrick dew cap and a Kendrick heater around the corrector. I do not have the super-duper heating controller, just the normal one.

Does anyone know of how to find the right balance of heat setting to just prevent condensation on the corrector and yet be at a minimal so as not to create thermal degradation? The 9.25" image is so sensitive to thermals. For example, just reaching my hand down to collimate the secondary creates thermal fluctuations that last for at least 30 sec before dying down.

It seems like the best way to go about this is still to get a Dew Buster or the Kendrick "deluxe" controller. Right now, I just set it just below "medium" and hope for the best. Some nights I think there is too much heat input to the heater strip as the images never quite settle down, but finding that point is difficult. One gets really shy about turning it down too much when everything around is dewed up and wet.

Thanks in advance for any opinion on this.
Ivan


December 15, 2004 04:22 PM Forum: Equipment Talk

Oil-spaced Apochromats/ Objective Elements

Posted By Ivan Ong
I have been reading up on 5-6" refractors and some (like the TEC 140) have oil spaced objective lens elements. I beleive some of the older AP's might have it too. Question is what is the longevity of the oil? Most organic oils will eventually react (oxidize, turn yellow, change viscosity, cloud, leak). How risky is this for a high end refractor? Will wide temperature swings affect the stability of the film? I like the TEC a lot but I wonder about this oil thing.

Thank you in advance for your opinions.
Ivan

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