A new addition to my telescope family :)

[dazcaz]

Hello all, it's been a while since I last popped on here.

I just thought that I would say hello again and tell about my new toy.

Walking down a local high street, we popped into a Cash Converters looking for 2nd hand games for my son's computer game habit. No games found, but we had a look around.
My wife called me over to where she was standing. She was standing next to a Celestron C4-R on it's CG-4 mount (complete with polar scope), completes with all accessories and tool kit.

When I enquired about the price, the man went of to check.....

FIFTY QUID!!!!!!!!!!!!!!!!!!!!!!!!!!

It all looks in good condition. No dents or scratches. Glass looks clean. Focusser is smooth as are the manual slo-mo drives.

For 50 quid I am very happy.... Assuming it's all still in alignment. I won't know for certain until it sees it's first light.

Ironically as we went into the shop, it was a cold but sunny day in Cardiff. As we walked out of the shop, with new telescope, it was pouring with rain.
Why does this always happen? New scope= nonsense weather

So now I have three 'scopes.
8" Skywatcher Newt on HEQ5
5" Skywatcher Supa-Trak
4" Celestron refractor.

Somebody on here once warned me when I bought my newt, that it never stays the only scope. The collection builds

This is my first refractor. I'm hoping it's as good as the old reviews that have read.
I see a few on here have this scope.
What are your views on it?
Was it worth the 50 quid I spent on it?

Hopefully the skies might improve for a quick session in the garden tonight. If they do, I will let you know of my first findings.

[David Frydman]

Excellent purchase.
This scope should perform very well to high standards.
Does it have eyepieces?

Enjoy using it.

Regards, David

[dazcaz]

Yes it has a 20mm Plossl and a 3X achro Barlow. The latter looks quite cheap. I have a load of eyepieces from my other scopes so I'll be able to get the most out of it. It also came with the 6X30 finder scope which some reviews said was an extra.
I'm very happy with it. Might get to see Jupiter tonight if the clouds have big enough gaps in them :

[dazcaz]

First light Jupiter and it's four main moons.
Just using the 20mm Plossl (50X mag) the two main bands were clear and sharp. Colours were great but there was a touch of a blue around the edges if not looked at properly. Generally the view was stunning. Not bad at all for 50 quid!!!

One thing I did find annoying was the exit pupil on the Plossol was tiny. It was all too easy to get nothing but blackness when looking into the eyepiece.
I am new to refractors and this might be par for the course, but it was annoying. Using the 3X barlow was very difficult because of this.
I hope this is just the exit pupil and not a fault with the optics.
Maybe you guys can advise me on this.

The view through the Barlow was very nice indeed, but the limitations of not being able to see through the eyepiece most of the time made this difficult.

Next time out, I will use the eyepieces from my other scopes as a test.

I do miss a motorised mount. Trying to reach for the slo mo stems and the focussing knob is not easy. Maybe I will get used to this overtime
Maybe I'll buy the motors

Overall, this is the best 50 quid I have ever spent

[David Frydman]

Do you wear glasses when using the refractor?
I don't think you mean exit pupil.
You might mean eye relief.
This is basically the distance from the rear surface of the eyepiece to the position you put your eye at along the optical axis.

The exit pupil is simply the clear aperture 100mm divided by 50 i.e. 2mm.
And 100mm divided by 150x using the 3x barlow. i.e. 0.7mm.

Assuming you eye pupil is say 4 to 5mm. it should be easy to see Jupiter as the exit pupil falls within this 4 or 5mm.
With a 0.7mm exit pupil you might see floating things in your eye as shadowy shapes. Most people have these.

With a 20mm Plossl eyepiece I would expect the eye relief to be perhaps 10mm. This is plenty without glasses.

You might find that a long eye relief, LER eyepiece is better, but with a sliding or rotating eyecup to position your eye correctly.

Does the 20mm Plossl have a rubber eyecup?

Try your other eyepieces, which you are used to.
Which eyepieces are you happiest using?

I would expect the 100mm refractor to perform brilliantly at 150x with good Seeing conditions.

The false colour may be due to the O.G. , the eyepiece or even your eye or any prism you might be using.
A 100mm f/10 scope exhibits some false colour but not much.
It does not bother me, but some people use a filter, perhaps a Baader fringe killer to overcome it.

But for £50, I agree an excellent buy and why spend more.
Just try the eyepieces you have.
It could be the 3x achromatic Barlow, probably two lenses also introduces colour. There are I think 3x barlows with three elements.
I think the Russian TAL 2x and 3x barlows are good, perhaps only two element.

This was only your first session.
Try double stars.

Clear skies,
regards, David

[David Frydman]

Try an eyepiece giving 100x. It might be easier to start with.
Either a 10mm preferably good eyepiece or a good 20mm and a good 2x barlow.

It may be that at 150x if you are not used to it, Jupiter is moving too fast for you to keep track and at 100x you will have more luck without a motor.

A motor is not essential but it takes practice to use slow motion hand controls.

David

[dazcaz]

Thanks for the in depth reply David.
I do not wear glasses.
Yes it could well be eye relief. The Plossl does not have an eye cup.
On my other scopes and eye pieces I do not normally have this problem, so I was a bit surprised by it. I will try my other eyepieces in this scope.

I use a 90 deg adapter with a flat mirror, so no prism as such.

This viewing was a very quick and impromptu test. Just keen to get first light.
My next test will be less rushed and I'll try different combinations of eye pieces and barlows etc. It appears that I also have a C mount, so I might be tempted to connect one of my DSLRs to it and see how it works.

The mount could be better, but it's adequate.

Darren

[David Frydman]

The 20mm Plossl has an apparent field of about 48 degrees.
At 150x the real field is about 19 arcminutes.
If your eye is not in the right place maybe 15 arcminutes.
Jupiter would move this distance in roughly one minute from one side of the eyepiece to the other.
That is probably why you are seeing a lot of black.

So try first 100x, if you have with a wide field eyepiece.

A new dedicated wide field eyepiece will cost you more than you paid for the scope.

Regards, David

[dazcaz]

It wasn't Jupiter moving out of the field of view, it was not being able to see anything unless I moved my eye around. If my eye was in the wrong place, all I got was blackness. Pitch blackness, not the light polluted pseudo blackness that I normally see through a telescope
This difficulty in seeing through the eyepiece is new to me. It had me worried, but I think that all is OK with the scope as when I do get to see through it, the sight is superb

Darren

[David Frydman]

Dear Darren,
The blackness might be if you were using 150x on a 100mm scope the background is quite dark.
I don't know why you had difficulty except may be the high magnification without a drive.

The adapter is a T 2 adapter or less correctly a T adapter (originally Tamron I think).
A C mount is for cine lenses.

I used to use a 123 mm f/5 refractor and 90mm longer focus refractor at 145x with no problems, but with an altazimuth mount undriven. Also 120mm f/8.3 at 250x and a 100mm f/12 for a while.

But I used refractors for many years, so had a lot of practice.
I don't think I had a drive on my refractors, although i used a driven observatory 135mm.

Good luck.

Regards, David