AN OBSERVATORY FOR THE GARDEN

What a lovely gesture!

 

Well, while I'm waiting for the Observatory Dome to arrive in around 4 weeks time I thought I'd show you what equipment an amateur astronomer can gather if he's not careful. Let me say first that a lot of people get a lot of satisfaction and use out of a pair of binoculars, while not needing or wanting anything else, and probably know their way around the heavens more than I will ever will/do
My first telescope was a secondhand Celestron 8 inch diameter, [aperture], Newton type which I bought from e-bay in an auction. I actually thought the seller lived in Bridgenorth, which is not that far from me, only to find he lived in Bridgewater, Somerset!! , which meant a nearly 400 mile round trip It came with a motorised tripod but it was old and sounded like a coffee grinder when the motor was operating so I knew I would have to get a new one.

It was my learning ground and I did a lot of research and plucked up enough courage to strip the telescope down completely so that it was just an empty cylinder, cleaning the two mirrors, putting anti reflective material on the inside of the cylinder [it's called flocking], install a new up to date focuser, fit it with a device called a TELRAD which basically enables you to find your target star a lot easier

, fitted a new [right angled] Finder scope which also helps you find your target star, plus a few other things. It may be an old telescope but it's been refurbished and brought up to date so it's performing as though it's new and it will stay in my collection.

 

Knowing that I was going to buy another, bigger telescope, I decided to upgrade the tripod mount to the best I could and bought an NEQ6 which is a GOTO mount, [in other words it is computerised and motorised, and will point [go to] any star you dial in. It also knows, via GPS, where you are and that makes things a lot easier when calibrating where Stars are in the skies in front of you.


I then bought the bigger telescope that I wanted, which was a 10" diameter [aperture] Newtonian type and again it's a great Telescope gathering in more light and giving brighter images and again I have learnt a lot from it. One of the "problems" though with a Newtonian Telescope is that they need the mirrors to be calibrated, adjusted , [called collimating] quite often to give the sharpest images, which although it doesn't take long can be a pain!!

I bought a TELRAD for that too as, believe me, although you would think that pointing a big telescope at the skies and zeroing it in on a particular Star that you can actually see right in front of you would be easy....it ain't and can be very frustrating trying to get it in view!!

 

So having got as far as I had and finding that Astronomy is such a huge subject I guess I got really hooked in learning more and more [which is hard as I have to read and use things several times before I can understand], I decided to try other kinds of Telescopes. I try to do a lot of research, trawl through the many Astronomy forums, gathering as much information and opinions, [good and bad], about anything I'm interested in. That brought me, after a fair while, to decided to invest in a 9.25 inch diameter, [aperture], Celestron SCT [Schmidt Cassegrain] Telescope which is a completely different design to a Newtonian type.


It's a great Telescope and I probably like it the best of all as it gives great images and also only needs calibrating [collimating] every so often It's a very versatile Telescope. is a lot less cumbersome and easier to put on the mount of the tripod.

 

Now, if you're sane, you would have stopped there but........ The Webmaster of an Astronomy Forum that I like and am a member of. decided to sell a lot of of his gear and as he is an technical perfectionist given to modifying and upgrading everything thing he has.......... I bought a Maksutov Cassegrain 180 [nearly 8" diameter or aperture]Telescope from him. It was in perfect condition, have been modified and upgraded in every thing possible, including an electric focuser, and I'm very happy with it. It's supposed to be used solely for observing planets, [and Mars will be coming close next year], but I've used it for Deep Space Objects and it's absolutely great......having said that it is much harder to target a specific Star with it as it has a much narrow field of view than the other scopes.

 

No, ..........well, yes,.........there already has been, Sheal. I've been thinking of doing some astro imaging once I've got settled into the Dome. So I've bought a QHY8L CCD Colour camera to use on the Telescopes.




I bought it from the same Webmaster of the Astronomy Forum of which I'm a member knowing it would be in great condition. There are two types of CCD cameras used for astronomy...Mono and Colour, all have to be controlled by a computer when using them. Mono type sensor are more sensitive to light and can gather more distant light more easily that colour CCD. But the snag, for me, is that you have to take three images each with a different coloured filter [red, green, blue] and then merge the three images together to get a colour image [there's more to it, but that's the general picture [pardon the pun], whereas with a colour CCD you can take just the one shot to get an image although the colour CCD sensor is not as sensitive as a mono sensor and gives less resolution, etc. So, I decided that I'd rather spend more time behind the Telescope than in front of a computer having to spend hours, days, months [as some do] turning a mono image into a colour image. I do know my way around a camera, but astro imaging is a completely different "animal" so it'll be a while before I start anything serious attempts. Also, as you know, it will take me a while to lay a floor within the Dome, install the wiring, and power it all up. etc.

 

Yep, as soon as I've got my head around using the Dome properly, Sheal. One of the other advantages of a colour CCD camera is that it is a "one shot" type and so if the weather is cloudy you still might get a shot of taking a image. With a mono if the weather is cloudy, your chances might not be so good at getting three images.

 

I thought I'd continue to show and explain what extra "essential" bits of kit, apart from the Telescope, an amateur astronomer will believe he/she needs to improve their enjoyment of their hobby.
So with a Newtonian Telescope the light enters the top opening and goes down to a large curved mirror at the bottom. That light is then reflected back up in a cone shape to a small mirror just inside the front of the telescope which reflects the light upwards and to an focuser and eyepiece where you can adjust the focuser to get a sharp image.


Usually, most telescopes are equipped with very basic extras of questionable quality and usually an owner will have done some research and decided to get better additional equipment. One of those will be a Finder Scope which is mounted on the main telescope and because it has a greater field of view can be a great aid to finding Stars, etc. The basic Finder Scope is what is a called a "straight through" type

They're very useful but you can end up with neck and back strain trying to look through them due to the angle that the main telescope is when pointing to the skies. So there is another type of Finder Scope which is called a Right Angled type which makes it easier to peer through it especially as the eyepiece will rotate 360 degrees.

 

So, in general, I have two types of telescopes, Newtonian and Schmidt cassegrain. The Newtonians are open at the top and use two mirrors to bounce and focus the light path up to a focuser and an eyepiece. The Cassegrain telescopes are a bit more complicated in that they bend/fold the light path several times before it reaches the eyepiece, they also need less calibrating of the mirrors making life simpler and are usually shorter and lighter than their Newtonian equivalents. There are also three variants of this type of telescope, Schmidt Cassegrain, Maksutov Cassegrain [and I have both of those], and Newtonian Cassegrain where there a differences in the way the light path is bent/folded.





If you look at "6" on the diagram you'll see a device called a Star Diagonal.



The Star Diagonal is inserted into the back of the telescope and it contains a prism or mirror which reflects the light going into the telescope up into the eyepiece. The focusing is done by turning a small knob on the back of the telescope which moves the main mirror inside the telescope backwards and forwards to get a sharp image. Usually, the one that is supplied with the telescope is not exactly brilliant in quality and so most astronomers will buy a better one. Again, there are variants of Star Diagonals because there are two common sizes of eyepieces, [1.25 inch and 2" inch], so you can get Star Diagonals that will only accept a 1.25 inch eyepiece, one that has an adapter that will accept a 1.25 inch and/or a 2" inch eyepiece, or lastly one that will only accept a 2"inch eyepiece. Some people think a prism Star Diagonal is the best type, while others think the mirror type Star Diagonal is best.......me, so long as it does the job I'm not bothered!!

 

The Web sometimes gives you problems rather than solving them and when I tried to buy a UHC filter from America for my scopes I ran into problems. I got through all the processes and up to the Buy Page when it came up with "cannot deliver to this [UK country]..... So I mentioned it in a thread on the Cloudy Nights Forum and immediately the Company that makes the filter came onto the thread, apologised and put me onto another buying site where I was able to buy it! Now that's what I call Customer Care.

 

Brilliant result Well done to the company that makes it.

 

Hmmm, running into problems with the lead time for the Observatory. The manufacturer says there will be a delay of a couple of weeks due to having to make "minor" repairs to the molds to ensure the finish quality is top grade. I'll just have to divert myself with doing jobs that I've been putting off.