Few Images From 22nd April with Intes MK67

[PembrokeSteve]

 

Hi,

A few images below, from the evening of 22 April 2021. 
Imaged with my Intes MK67 and ZWOASI178MC camera. 
The seeing was rather good and only a very slight breeze, so I had a chance to use my x2 Barlow !

Images focusing mainly on Plato, Vallis Alpes and finally Montes Jura and Sinus Iridum

Image 1:  Wide Field Image - Taken using camera resolution 3096 x 2080
Image 2:  Plato and Vallis Alpes - Taken using camera resolution 3096 x 2080 and x2 Barlow
Image 3:  Vallis Alpes - Taken using camera resolution 1920 x 1200 and x2 Barlow
Image 4:  Montes Jura and Sinus Iridum - Taken using camera resolution 3096 x 2080 and x2 Barlow

Processed using Autostakkert, Wavelets in Registax and then Affinity Photo.

Regards,
Steve

 

[vlaiv]

I don't think you need a barlow with ASI178 and F/12 scope.

First image is very good - other three are a soft due to over sampling.

[PembrokeSteve]

Hi, Vlaiv

Thank you for your advice. I must admit, I was getting a little frustrated trying to obtain the tack sharpness in my barlowed images.  So basically with the 178MC and the Intes, for Lunar , I am better off selecting a suitable ROI, and afterwards cropping them, to obtain close ups rather than using the Barlow?

Regards,

Steve

[wouterdhoye]

Well cropping will not get you any closer or give you extra magnification. You just need to mate your camera and aperture. And that taking into consideration the use of filters. e.g. the ASI 178 with 2.4micron pixels will reach critcal sampling at f/12. If you'd go to longer wavelengths like red of IR it even drops to f/9. So a less powerful barlow is the best solution to get you f/7 telescope closer to critical sampling focal ratio. 

if you used a luminance filter you also have to take into consideration softness due to atmospheric dispersion. you can actually use color filters with a color camera to cope with this. I used a green filter for below image taken with a 6" f/12 scope. pixel size is 2.9 micron, so in fact a little bit undersampled.

Clear skies,

Wouter.

 

[vlaiv]

17 minutes ago, PembrokeSteve said:

Hi, Vlaiv

Thank you for your advice. I must admit, I was getting a little frustrated trying to obtain the tack sharpness in my barlowed images.  So basically with the 178MC and the Intes, for Lunar , I am better off selecting a suitable ROI, and afterwards cropping them, to obtain close ups rather than using the Barlow?

Regards,

Steve

You should select ROI based on two things:

1. frame rate you want to achieve

2. correction of your scope. Some scopes are diffraction limited only on axis - or close to it and further away from axis have significant aberrations. Newtonian is example of that - coma gets worse off axis and with fast newtonians - very quickly, so they benefit from small ROI.

What F/ratio is your scope? Your signature says it is F/7 but I can't find such reference online.

Intes MK67 is always quoted at F/12 being Maksutov (I'm asking because of both your signature and @wouterdhoye mention f/7 for MK67).

[PembrokeSteve]

Hi, Vlaiv,

You are correct, i have just checked out my MK67 and it indeed is f12, with focal length 1800mm, 6 inch mak.  I have no idea where i got that f7 from on my signature !

Also thanks Wouter for your kind advice, all very much appreciated.

Steve