Posts Made By: Ivan Ong

Hi all, I have a small dust particle on the chip of my ToUCam that will not come out with blowing. Looks like I will have to be more drastic. What is the correct way of cleaning it?

Thanks,
Ivan

Hi all, need your expert opinion. Shot this test shot under very light polluted skies. Here is my imaging train:
Tak Sky90>Camera Angle Adjuster>Focal Reducer>IDAS LPS 2" filter>Wide Mount+T-ring>Canon 20D.

The left photo is adjusted in photoshop, but the right one is the left photo cranked up in contrast. Note that the field of illumination is very strange. There even seems to be a horizontal stop on the lower edge.

Here is a composite view from Ptolemaeus, Alphonsus, Arzachel etc.
Taken with my little 'ol Nikon 4300 afocal through my C9.25", stiched together with Photoshop.

Clear skies,
Ivan

Recently I acquired a Televue 60mm APO. I have enjoyed many nights of grab-'n'-go observing with this little scope and have been very impressed with the optics. For example, Rigel is a very easy split with a 9mm Nagler, clean and very pleasing. Saturn at high powers yields nice views of Cassini's Division and The main Southern Equatorial belt with hint of minor coloration of other belts. There is a crispness to the optics that makes you fall in love with this little scope.

Yesterday, I was in the Blue Ridge Mountains and decided to try the Perseus Double Cluster with this scope. I used a T-ring 1.25" adapter and my Canon 20D. Exposure was 4 min, manually guided.
I wanted to evaluate whether this scope will be a nice 360mm wide field imager. Tonight I processed the images through photoshop and I am rather disappointed. Look at the obvious elongation of stars on the peripherals, I estimate 40-50% of imaged area is not acceptable. This cries out for a flattener but I doubt anyone makes one that can be used for this model. Maybe Borg adapters and Tak's 60C reducer/flattener?

The other thing that makes me hesitate about using this as an Astrograph is the lack of a rotating focurser like Takahashi's Camera Angle Adjuster. Framing a shot by loosening the 1.25" compression ring immediatley required refocusing through my laptop software, so that is not good as the routine gets old quickly. Once again I believe a Borg rotating focuser may be employed as they have a 1.25" adapter for that.

I would conclude that the Takahashi FS-60C is a much more suitable scope for imaging than this, but then that should be fairly obvious given the accessory support that Tak has.

The Televue was primarily designed as a grab and go visual scope, and it certainly lives up to its billing there. Another use may be for birding photography. The draw tube/helical focuser will make for rapid terrestial photography.

Clear Skies,
Ivan

First time out with my brand new Sky 90. Here is 3x5min, ISO1600, CF2=on, MaxIm, Photoshop CS, Canon 20D.
The wind was howling and bitter. One of my gloves blew away when I took it off to adjust my tripod. Yes sir, just plain blown away off the Blue Ridge Parkway. But the great thing with this compact little scope is the FOV is so wide that it is impervious to the wind! I was manual guiding this, and used a reducer on the Tak, and a 2" IDAS LPS filter.
LOVE THIS SCOPE!

Here we see the Jewel Box of the North, the sapphires of the Christmas Tree Cluster, and a tiny cone nebula lurking nearby.

p.s. If you see a black bear in Spring with one right glove on, call me. He can have my other.
Ivan

Happy Saturday!
Here are the two open clusters M46 and M47 I shot last weekend. Always a very pleasant view in any wide field scope. I shot this with a Canon 20D, IDAS LPS filter, Tak 90 with reducer, manually guided 3x4min at ISO1600.

Thanks for viewing!
Ivan

Hi all, I am continually amazed what my new little Sky 90 can do! Here is a photo with the focal reducer/flattener and 3x5min with Canon 20D at ISO1600 and noise reduction on. Images combined with MaxIm DL. What a fun little scope this is! While the photo is not up to standard of the many pros on Astromart, I want to humbly encourage the aspiring astrophotographer wannabees that if I can do this, you can certainly do even better!
Ivan
p.s. oh by the way, The IDAS LPS filter is amazing. You should not be without one!

Wow, this one was very difficult to capture with a DSLR camera. I never saw the image until after the stacking and processing! Through the use of an IDAS filter, there was enough signal to noise seperation and this is the result of a 5-stack of 5 min exposures. Scope: Tak 90, reducer. Camera: Canon 20D, ISO1600, noise reduction on.

Thanks for looking!
Ivan

Hi all, I enjoy splitting double stars and am considering whether it is worth to look into a bigger aperture than my current 4".

Let's say I want to split down to about 1.3" or so, nothing tighter. Let's assume two stars of magnitudes differing not more than 3 units at this separation, both stars being brighter than 7.

An APO scope with an aperture of say 102mm has a theoretical resolution of around 1.15". An APO scope with an aperture of 128mm is 0.91".

My question is, assuming steady skies, is there an advantage in this case for looking at the 5" over the 4"? Or is the 4" more than sufficient? Let's assume both the optics are very well figured and corrected respectively.

Thanks,
Ivan

I've had pretty good luck in using the IDAS LPS filter for astrophtography with my Canon 20D. It appears to be fairly effective in removing remanant light pollution from the site where I image. Here are a series of 4 photos from my backyard. The top ones were taken last night, 15 Sec at ISO800 and it was raining and misty. The bottom ones were taken this morning when it all cleared up. These were taken with and without the LPS filter. These photos are as-is and not color adjusted. Notice that at night the filter is fairly effective in removing the yellow glow from streetlights. In fact, the night shot through the filter looks fairly gothic. On the other hand, taken in the morning, the filter bleaches out the warm morning tones of sunlight.

Scope: Sky 90 with Canon 20D.
Ivan