Altair Astro 8" f4 Imaging Newtonian

[earth titan]

After umming and procrastinating for months, I finally placed an order for a dedicated imaging scope. It probably means I shall need to replace my mount sooner rather than later, but we'll see how we get on.

In the end I decided on an Altair Astro 8" f4 Imaging Newtonian. Reasons for the decision?

1. Internal baffles
   
2. Nice robust focuser
   
3. F4 (good job I like collimating and fiddling)
   
4. Made by GSO to an Altair spec
   

The clincher was the fact they were on offer over Christmas, for £370 with a coma corrector.

Thought I would post a review, form the unboxing to 1st light (if the skies ever clear) and some images when it's all up and running.

It will be run initially on an HEQ5, but I know I might have to go down the EQ6 route eventually. Will see how we get on though, as I would like to keep the kit relatively portable.

So here we are then. Boxes arrive nice and safely from TNT.

[earth titan]

So what did I get for £370 then?

1. Scope
   
2. Coma corrector
   
3. Finder
   
4. Tube rings
   

Overall impression of build quality is good. It has been built to a price (thank goodness) but nothing essential seems to have been missed off the spec. There are even one or two things which are above and beyond/

Firstly the coma corrector

Looks good and well made. I have no experience of these as yet (this being my first) but it is certainly a hefty bit of kit and seemingly well made. It came with a couple of extension tubes and a T thread adaptor.

[earth titan]

Focuser

Nicely made and very robust.

It was slightly out of square when it arrived, but this was simple enough to rotate to perfect position.

I have tested it with coma corrector and Canon100d0d mounted in it and it showed no signs of slipping or moving.

Action seems nice and smooth.

[earth titan]

OTA

Nicely finished in a good quality white paint.

Tube rings are a little cheapish (bare in mind the price though) and will do the job fine. Being fairly light weight, keeps the scope mass down - which is good for my HEQ5.

Baffles are nice and should go someway to improving contracts.

Mirror seems clean and in excellent condition (this was an ex demo scope)

Fan on the rear of the OTA seems more than capable.

Weight of OTA with rings, dovetail and coma corrector 9.8Kg which isn't bad, but trying to keep whole assembly down to 13 Kg (my target) will be a challenge. I know the HEQ5 is rated at 17Kg and 50% is suggested for imaging but until I can upgrade to EQ6, it will have to do.

I have ordered an extension bar today, which will make balancing a lot simpler.

Will post some more pics this evening, when I get a chance.

[earth titan]

Finder

Finder is ok considering the price. Has a nice option to allow the fitment of 1.25" eyepieces, although it wasn't the scope in the pictures of the advert.

[Deneb]

Those baffles look really good, can we have a picture down the tube please...

Nadeem.

[earth titan]

I'll try......

... bit dark down there so I'll see what we get.

[earth titan]

I've now had a chance to check the finderscope and it makes it an even better deal than I thought.

Advertised to come with a 8 x 50, it has shipped with a 10x60mm Right Angled Illuminated Finder (erect image, variable illuminator, finder bracket, multi-purpose base).

Spoke with Altair and they apologised (there was really no need as this is a far better finder) as the one advertised was badly scratched.

Even better news, Altair are going to be supplying a focuser for this finder to allow autoguiding in the next few weeks, so this should get me down to around 11Kg all up.

[terrym2002uk]

Aside from the tube rings that looks like a great scope. I look forward to seeing what you can get out of it. Enjoy.:

[themos]

That scope has been on my wish list for a while...

[blinky]

Same scope i have and i use it on an HEQ 5 along with a william optics ZS70 in he obs with no problems.

The problem i did have was collimation or more specifically, holding on to it! Check out my blog to see what i did with a tube of silicone, that has made it 1000% better! At F4 your collimation needs to be spot on and mine still needs a ting tweak, but you will be amazed at how much more light it pulls in.

Sent from my Scroll Excel using Tapatalk

[earth titan]

Thanks Blinky.

Have just checked mine and the mirror has a huge amount of slop in the cell. Think I may need to make the same mod...

[Stephen]

Hrrm, I just ordered the same scope!

Guess I best buy some silicone then

[Macavity]

Nice one! They're fairly similar to my TS/GSO F4 scope but, for about(?) the same price, might well be worth the baffling. Also, with the secondary mirror suspended further inside the tube, you might not have to "scrape" off the FROST after a while...

Aside: Altair Astro sell secondary heaters, though I sense the annular ones are supposed to stick directly onto the back of the mirror - Which SEEMS to be cemented into the mirror cell?

[earth titan]

Silicon now supports the primary, as I picked a tube up yesterday and spent the evening stripping a brand new scope apart . Wife walked post and tutted, whilst shaking head.

By the morning it has cured enough and the mirror is much more secure in the cell. The silicon is nice an flexible so allows some movement.

Tube reassembled and ready for the next stage. More tutting...

[earth titan]

Postie arrived with my extended counterbalance shaft this morning. Arrived nice and promptly (only ordered it on Thursday over the phone) from S&S - so credit to them for good service.

Fitted. Works a treat. Allows the set up to balance beautifully - moves with just a touch of the finger.

Woweee the office is a mess. Almost embarrassed - but not quite.

[earth titan]

Checked collimation and found to be out so got out the laser and tested the security of the mirror.

To collimate a Newtonian, I always use the barlowed method which I find works every time and is the only real way to do it. If you haven't tried it I strongly suggest you have a go. It works with any cheap laser collimator and the results always match the result I get with just a cheshire.

http://www.cameraconcepts.com/barlowed%20laser%20collimation.pdf

After collimating and then moving the scope a lot through the various arcs, through both vertical and horizontal, the collimation holds.

Thanks Blinky.

Now if only the clouds would part, I could get on with some imaging. Oh well - time to go make a bahtinov mask for it.

[Stephen]

Looking good Tom!

Quick question, was the primary already centre spotted, or did it come with a donut to apply?

I like donuts nom nom nom ....

(Edit) Oh you also reminded me, f5 mask isn't going to go too far ...... time to list it and ORDER (I'm lazy ) a new one

[Tim]

Good review Tom, nice and thorough. I have a similar TS/GSO scope without the baffles (will be for sale when the boards return).

Two mods/accessories that are well worth doing are flocking the tube, at least the section opposite the focuser, as the grey paint that GSO use will reflect some light, and it will detract from the image.

And secondly, get a showercap/dustcap from FLO to keep the light out of the rear of the primary cell. Even ambient skyglow reflected from the floor with give you an odd pattern in long exposures that you cant easily process out (found this out the hard way )

Looking forward to seeing your results!

Tim

[Tim]

Oh yeah, thats the other thing, double check the centring of the donut, mine was miles off and it makes a big difference at F4!

[earth titan]

Hadn't thought to check the centring of the 'O' ring on the primary.... Kind of relied on the manufacturers at least putting that in the right place.

Will check if there are any problems.

Was looking at focking the tube between the baffles. Just bought soem form Wilkos so praps I'll use a sheet there.

Thanks for the tip re the end cover. Will have to think of something to fit over then end.

[earth titan]

Well there we go.

An evening with full cloud cover and stuff all on telly.

Ready to roll.....

£4.00 all up. Made from a plastic presentation folder, a roll of insulting tape and some Evo-Stick (love that smell).

[Stephen]

And secondly, get a showercap/dustcap from FLO to keep the light out of the rear of the primary cell.

Do you have a direct link for this Tim? I can't seem to find what you are describing.

Cheers

[ollypenrice]

I found that the length of the coma corrector hung my fairly heavy CCD gear too far out for the chip to remain orthogonal. I suspect that the flexure came from the tube itself. However, there are good DSLR images out there taken with this scope. These are lighter cameras and do really benefit from the fast f ratio.

Olly

[earth titan]

I agree Olly. I would imagine any heavy kit will cause some deflection.

I'm going to be using a Canon 1000d which is about as light as I can get, and I'm hoping the fast f4 will really aid the imaging and keep noise down.