More imaging with a Skymax 127, an SVBONY SV605CC OSC cooled CMOS camera and AstroDMx Capture.

The SV605CC was fitted with a 1.25” nose-piece and an SVBONY UV/IR cut filter. The camera was fitted directly into the visual back without the use of a diagonal. The Skymax 127 Maksutov was motor focus modified to give very fine control over focusing.

Auto-guiding was done by PHD2 running on a separate computer using an SVBONY SV165 guide-scope fitted with a QHY-5II-M guide camera.

As usual, the Celestron AVX GOTO mount was placed on marks on the concrete base which give a fairly good polar alignment. AstroDMx Capture passed the time, altitude and location coordinates to the hand controller via the INDI server. The hand controller which now contained all of the correct information was set to its previous alignment and was unparked by AstroDMx Capture.

PHD2 auto-guiding

With such a long focal length telescope as the Skymax 127 it helps to be autoguiding when an attempt is made to plate-solve prior to centering the object of interest. This is to make sure that we have round stars rather than elongated stars in the image to be plate-solved. Of course, guiding must be switched off before the scope/mount is moved onto the object of interest. Guiding must be switched back on as soon as the mount has stopped slewing.

The equipment used

Using the procedures outlined in the previous article, AstroDMx Capture was used and the mount/scope was sent to Regulus, plate solved, and focus checked with a Bahtinov mask. It should be noted that quite long exposures should be used for plate solving to be sure to have enough stars in the field of view.

AstroDMx Capture then sent the scope/mount in turn to the Hamburger galaxy, NGC 3628 and then to M51.

AstroDMx Capture captured 2 hours worth of 5 minute exposures of the Hamburger galaxy.

The images were stacked in Siril and post-processed in GraXpert, Neat Image and the Gimp 2.10 with Starnet++.

Star removal techniques involving Starnet++ as a Gimp plugin were used so that the galaxy could be processed independently of the stars and then the stars added back.

These techniques were also used for the other two objects (M51 and M104) imaged for this article.

The Hamburger galaxy NGC 3628.

The mount/scope was then sent by AstroDMx Capture to M51, plate solved and M51 centred. 

AstroDMx Capture captured 63 minutes worth of 3 minute exposures of M51

The images were stacked in Siril and post-processed in GraXpert, Neat Image and the Gimp 2.10 with Starnet++.

Starless M51 image being de-noised in Neat Image

M51 the Whirlpool galaxy

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On a separate night the Maksutov was fitted with a larger, 50mm, F=190mm guidescope with a Touptek guide camera. This should help with guiding such a long focal length scope as the Skymax 127.

The focus was checked on both scopes using Bahtinov masks

A small Bahtinov mask was used to focus the guide scope on a bright star so that the focus of the stars is optimised for auto-guiding.

AstroDMx Capture was used to send the scope/mount to M104 the Sombrero galaxy, plate solve and centre the galaxy in the field of view.

AstroDMx Capture capturing just 8 x 3 minute exposures of M104 before the clouds came in.

The images were stacked in Siril and post-processed in GraXpert, Neat Image and the Gimp 2.10 with Starnet++.

M104 the Sombrero galaxy

More work will be done using a different guide camera with the 50mm F=190mm guide scope.

It is not the conventional wisdom that scopes such as the Skymax 127, with long focal lengths and limited aperture, are suitable for deep sky imaging. We have demonstrated that lack of aperture can be compensated by longer exposures. However, auto-guiding has to be good for this to work satisfactorily. Moreover, motor focusing in conjunction with Bahtinov mask focusing can yield satisfactory stars.

The SV605CC has proved to be a suitable camera to use with such a telescope.