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By Andrew Larmour
Absolute newby here - my first foray into astronomy. I bought a Saxon 1400mm 6" refractor secondhand complete with a EQ mount for a bargain price and I'm keen to get it working properly for both planetary and deep space observations.
I invested in a few extras such as a laser collimator and a 3x barlow. I think I have a handle on how it all works including the EQ mount. I took the scope out for a test over Easter - which just happened to coincide with a ISS transit of the full moon. Rippa, I thought, that would be great to capture on my first night of observations. The problem I have is the complete inability to focus the scope to anything like sharp enough.
I have some photos I took with the scope attached:
The scene with the normal camera lens for my daylight practice session
A shot of a distant house with the telescope (using a Nikon D7000 on a t-mount adaptor)
The same house with the barlow attached
A shot of the moon- no barlow - as sharp as I could get it - certainly no way to see the silhouette of the ISS with the scope this out of focus
When I was collumating the scope, I noticed a that the reflection on the primary mirror was not a single spot but rather a line
... which means that the laser on the collimator target is a line rather than a dot
I confirmed that this is not a problem with the shape of the laser beam coming from the collimator by showing the shape on my hand at a distance of 14m
I'm not sure if the distortion of the laser is the fault of the secondary mirror or the lens(es) in the bottom of the eyepiece mount. I'm also not sure if this distortion is what is causing the inability to focus the scope, but I suspect that both issues are symptoms of the same problem.
I'd appreciate any ideas on what to do next to resolve the focus issue.
I'm totally New to this hobby and i'm having trouble understanding something in stellarium.
I have ordered (not recieved) a Sky-Watcher Explorer 150PDS, which has a 25mm eyepiece 50degrees FOV as a default.
I also have a Nikon D810.
I wanted to get an idea of what my field of view would be with the 25mm eyepiece (30x on 750mm focal length),
and also what it would be With my Nikon D810 mounted shooting prime Focus - no eyepieces.
What surprised me was that it wasnt much difference between the frame and size of the object i get with 30x magnification (25mm eyepiece), and what i get with the Nikon D810 mounted.
I dont get this. What magnification do i get With my DSLR mounted with no eyepiece?
I own a Vixen ED-80 refractor which is used with a custom focuser by Telescope Service.
A Celestron f/6 SCT reducer corrector did not provide decent images either because it is not appropriate or because I did not maintain the correct distance.
I am thinking of buying the Sky-Watcher .85x Reducer/Flattener instead, as it is made for similar ED80 telescopes.
I do not know what is the correct distance of the SkyWatcher reducer for my setup and more important, I do not know if it will focus with the custom TS focuser.
Do you have any similar setup that you have used successfully?
I have an EQ5 telescope mount which i use for astrophotography. I have modified it with a motorised RA axis using a bipolar stepper motor - my thread for the build is here .
I want to expand the mount's tracking ability by motorising the DEC axis and using a guide scope/camera. I generally use the mount in fairly remote locations so would like to use a raspberry Pi for portability.
I understand that I'll need to use a Raspberry Pi Camera Module for the guide camera.
The capability I want is:
1. guide the mount along RA and DEC axes using a guide star as feedback
2. track the mount using the RA axis only, and if possible continuously take 20-30 second exposures on the guide camera (this functionality is optional, but would assist in polar alignment of the mount)
I don't want any GOTO capability. I am very new to RPi and need some help:
- do I need to write code for this, or is there existing programming available for what I want to do?
- is it possible to avoid the use of screens (in the field)? My preferred option would be to flick a switch to start and stop the guiding, with another switch for alignment mode (or something simple like this).
- do I need to use any particular stepper motors/drivers for raspberry Pi? I'm using a bipolar stepper motor running quarter steps, with an A4988 stepper driver
- is the RPi 3 Model B+ the unit I should buy?