Collimating the C14 with a tri-Bahtinov.

Finally clear skies with a half Moon yesterday! so perfect for fine-collimating the C14.

Last week, astro-friend Erik (Hemiksem) could lasercut two tri-Bahtinovs, one for F11 native and one for the F7.5 configuration using the Starizona reducer.

This was the intial image before collimation:

Tri-Bahtinov image of the C14 before collimation

As can be seen on the image above, the collimation is pretty good, actually near-perfect. The principle of a Bahtinov is that the middle line is perfect in between the two outer lines. A Bahtinov does that with one axis (on set of lines resembling a star), and a tri-Bahtinov does that on three axis. By aligning the Bob’s knobs with the axis of the mask, you can easily adjust each knob untill the coïnciding middle line is perfectly centered.

Closely looking at the starting image, it’s clear that the 10 o’clock-4 o’clock axis line is a bit off. After some small tweaks with the corresponding knob it looks as follows:

A possible pitfall is that the collimation already needs to be near-perfect for this procedure to work. A SCT can be misaligned but still show an aligned tri-bahtinov. So take care to collimate as perfect as possible visually on a star first.

NGC7000 or “North-Americanebula”

Second light for the new ASI2600 MC Pro camera, this time used on the Sharpstar 76 EDPH F4.5 Apo. 70x300s or 5hrs 50m over three nights in the week of July 21th 2020. Over the nights there was a slight shift in image field which resulted in a mosaic like appearance. The gain setting was set to “Highest Dynamical Range”. Click on the image for a larger view.

First light ASI2600MC

(Click on the image to enlarge)

M51 14x300s SQM20 27MEI2020 ASI2600MC ESPRIT120 F7 Gain0 -10C 100% V2

Really need to learn how to use this camera and process the images, very different again from B/W and DSLR. The gain was set to “0” (“Maximum dynamic range”). Using the 120mm Esprit @ F7 native focal length of 883mm. As a first impression also the camera takes a lot longer to cool down compared to the ASI183MM and the files are pretty large at 50 Mb.