Archive for category Moon

Clavius with Mak Cassegrain 180mm

Date: 1/15/2011

Location: Sam Bruno, CA

Instrument: Orion Mak Cassegrain with Imaging Source DMK camera at f/d 15

Infrared Filter Astronomik IR Pro 742

Processing: Avistack for Image stacking, Astraimage Wavelet processing, Photoshop CS4

Seeing: 3-4/10

The use of the Infrared pass filter (pass wavelength above 742nm)  allowed to pass through the turbulence. Not only the image was much more stable but showed also improved contrast (compared to a regular Infrared Cut filter).

Even if the IR pass filter reduces luminosity, the moon is such a bright object that each frame integration time is still small (1/10 second by frame for this picture – about 1,000 stacked frames ).

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Copernicus with Mak Cassegrain 180mm

11/16/2010 at San Bruno, CA

Orion Mak Cassegrain 180mm with Black and white DMK camera on Takahashi NJP-Z mount.

Seeing: 4/10  and Transparency 3/6

I wish my DMK camera sensor would be larger than its 1/4″ size. It is perfect for planetary imaging but the field of view is too small for the moon!

This is taken at approximatively f/d 25 (f/d 15 with barlow x1.5).

Processing: registax v5, Photoshop CS4, and Astra image wavelet processing.

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Moon pictures, and considerations about collimation…

I took a couple of pictures of the Moon with my Celestron 9″1/4 schmidt-cassegrain and was quite satisfied with the result, compared to other pictures taken later in November.

Pictures taken on 2/1/2009 by 8.30 PM PST, with Orion Startshoot solar system imager II, and processed with Registax and Painshop Pro.

Theophilius, Cyrillius, and CatharinaStofler  and MaurolycusLicetus and Cuvier

Besides ok conditions, collimation made here the difference.  I clearly noticed that a poor collimation combined with turbulence seems to worsen quality of  images.  Seeing conditions being equal – even with turbulence – a better  collimation will very significantly increase the image quality.

Check the very comprehensive page of Thierry Legault on the impact of collimation on image quality.

I recently bought Bob’s knobs collimation thumbscrews, and it allows me to quickly collimate my SCT (looking in the eyepiece and at the same time moving the screws to achieve collimation…).

I looked at many threads / forum discussing laser collimation tools and it seems no collimation tool is perfect.  Star collimation is quite fast with Knobs  on the secondary of the SCT  and allows to achieve an acceptable collimation even if seeing condition are not perfect.  And the price of collimation knobs has nothing to do with pricey’s laser collimation tools…

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