Recently Browsing 0 members
No registered users viewing this page.
Just wondering what peoples thoughts are on the pro's and con's of the different types of mounts out there? Do Dobsonian mounts have issues on non-flat surfaces (like a garden) or can Equatorial mounts ever have issues getting out of line too easily?
From my other post, you all should realize 2 things about me. 1: I can't leave well-enough alone. and 2: I like to fiddle around with things. In my last thread, I got setup with my goto telescope and managed to control it remotepy with KStars or Stellarium and even got my CCD working so I can sit inside in comfort while stargazing.....ALMOST. I still have to run in and out to turn the focus knob. So....
There is a raspberry pi running the INDI server pointing the scope and managing th CCD. I have a nice little geared motor and a HAT board that I know how to connect and control with the pi to make the motor go fast or slow, or forward and backward. I can manage the machine work to create a connection to the focus mechanism for the motor. What I need to know is if there is already a DIY-ish or configurable driver for INDI. And yes, this probably is a post for INDI forum, but for some reason I can't get a login there. So, if anyone knows or has done this, thank you in advance for any information you are able to provide.
Very happy with it! Wish the sky were clear, but as we all know, when we buy astro equipment, it's cloudy! Argh!
The telescope was collected from David Lukehurst at noon and then we travelled back to Cambridge.
John Nichol primary mirror: 37mm thickness, Suprax. Hilux coated. Optics 1/8 PV wavefront 1/27 wave RMS. Strehl .95. Secondary mirror: 62mm MA.
Here a few photos:
I am thinking on grinding my own lightweight mirror (first f4 16", later f4 24"). The lightest and cheapest option is to get a thin blank and slump it in a decent kiln.
Anyone has longer term experiene with slumped mirrors? Overall doesn't seem to be more work than a normal (not pregenerated) blank.
Do I have to grind the backside as in case of normal flat back mirrors to avoid astigmatism? How do people support a convex back while grinding? Does it make sense to grind a hole in the middle for additional support? I am remotely considering a convertible Newtonian/Cassegrain system anyway...
I've finally got around to making my flats box.
I decided to go for a cylinder rather than the normal square as I thought it would maximize the amount of reflected light and limit any 'dead' areas. I could also use the Celestrons dust cap retaining pins to lock the flats box onto the 'scope.
I purchased some of the craft board that has a thin foam sheet sandwiched between two sheets of thick paper/thin card. In order to bend the card into a cylinder, I creased the board every 20 mm by pressing the edge of a steel ruler into the board. It took two of the sheets to make a cylinder big enough to fit my C9.25, with only a couple of cm trimmed off.
I then made a reinforcing ring/defuser holder from two strips of the foam board; this time creasing them at 15mm intervals. I stuck these level to the bottom edge so the joins were 90° to the main cylinder joins. These strips were cut wide enough to ensure that the diffuser cleared the secondary housing.
The cylinder was designed to lock into the C9.25s dust cap retaining pins so next I cut two keyways into the bottom outer side. They looked a little weak so I reinforced them with some Christmas chocolate reindeer plastic packaging!
Although the foamboard is quite shiny, I wasn't happy with all the grooves, so I lined the inside with white A4 paper. The Perspex sheet was cut to shape and hot glued into place onto the ledge.
Next, starting at the top, I notched the edge of the cylinder to run the LED string lights cable through and then started to spiral the LEDs around and down the cylinder.
The top cap/reflector was made from two discs of foamboard. One to go inside the cylinder and one to sit proud of the edge. They were glued together before being hot glued onto the top of the cylinder. The LED light string that I bought has an integrated on/off button as well as both up and down brightness buttons with a 3M sticky pad on the back, so I stuck this to the top cap.
As I had previously made myself a 'scope mounted power distribution box with aircraft sockets for power, I removed the 3 pin UK plug/ac-dc converter and soldered on an aircraft plug to match my 12 volt DC supply socket.
The lightbox illuminated.