Altair Astro 8" RC

[r3i]

After many months of procrastination I finally succumbed and ordered one of these tubes from Altair Astro. Ordering from them was hassle free and delivery was prompt.

So far I’ve only had chance to get the scope out of the box and give it a quick look round so this posting will only go that far – I’ll post more information as I go along but no idea when first light will be – with precision timing the clouds have well and truly descended and look like hanging around for a while.

There’s nothing like getting a nice big box in the post. The scope arrived well protected in a double box and encased in a polystyrene sarcophagus.

The overall fit and finish of the scope looks to be good, the carbon fibre tube looking particularly smart. I did notice on the photos that I took there were some marks around the secondary collimation screws, presumably caused during factory collimation, but I hadn’t noticed them during a visual inspection. It’s amazing what a flash gun shows up.

For mounting the scope and fitting a guide-scope, it has a Losmandy D series dovetail rail on the bottom and a Vixen dovetail rail on the top, which presumably you could swap over if required. There is also standard SkyWatcher type finder scope shoe. The front of the scope is protected when not in use by a dust cap which looks to have a secure push fit.

The focuser is a GSO dual speed unit with a linear bearing and a 2” travel that has both a metric and an imperial scale. It has a tension screw on the underside and a lock screw on the top. The focuser can be rotated by loosening the large silver locking collar. It comes with the ubiquitous 2” to 1.25” adapter. The focuser looks to be quite solid and the overall quality I would describe as satisfactory – the operation is smooth enough and certainly not rough. My experience of other focusers is somewhat limited, but in comparison to the Crayford that came supplied on my IKI 70ED (another Chinese scope that is sold under many guises), the IKI focuser is decidedly of a better quality: more substantial and a smoother operation. I’m sure the focuser will be fine in practice though I’ve always planned to upgrade to something like a Moonlite at some stage in the future. One good thing about the focuser is that the 2” accessory holder has 2 thumbscrews, which is more reassuring than just the one provided on the IKI focuser.

The scope has been designed to enable it to be used with a variety of imaging configurations and to this end it comes supplied with a set of extension tubes to provide the appropriate back-focus distance: one 2” and two 1” tubes are included.

The only minor gripe I have so far is that the scope did not come with any documentation, so details about how to collimate could have been problematic. Fortunately, manuals are available on the web for its sibling clones at Astro Tech: http://www.astronomics.com/main/documents/astro%20tech/astro-tech%20at8rc%20manual.pdf and Orion: http://www.telescope.com/assets/product_files/instructions/29361_09-09.pdf

So overall my first brief impressions are favourable. The next thing I want to check out is the collimation with a Cheshire eyepiece. Of course, the real proof of the pudding will be in the imaging but it looks like I’m going to have to put up with the obligatory wait for clear skies.

[wackyscot]

NICE!!!!!!! -very envious, enjoy using it

David

[ollypenrice]

Exciting. I'm hoping to get my hands on one of these in a little while. It's a nice upper focal length for mounts with EQ6 like accuracy. A guest who has one found that in standard trim it very nearly covered a full format chip without distortion. That's without the flattener.

Olly

[Marcus daniel]

F.Y.I I am using an Altair 8" F4 Newtonian, to honest, the Images an getting from this scope still amaze me, it is very, very good indeed. Mine doe's need collimating every time I use it, but that only take 10 mins max. With this scope being so fast the detail and light it collects in such a short space of time is excellent.

Good luck with it and clear skies!!!

[r3i]

Exciting. I'm hoping to get my hands on one of these in a little while. It's a nice upper focal length for mounts with EQ6 like accuracy. A guest who has one found that in standard trim it very nearly covered a full format chip without distortion. That's without the flattener.

Olly

Hi Olly,

That's good to hear.

At some stage in the future I'll be wanting a Focal Reducer for it to give more options. As I understand it, GSO's own was pulled some time ago due to some problem or other, and that there are various alternatives that folks have had success with such as the Astro Physics CCDT67, the TeleVue TRF2008 and I saw that Modern Astronomy have a couple of Intes Micro reducers that are supposed to be compatible. It would be good to hear if anyone has had any experience with these. Anyway, one step at a time!

[r3i]

Have spent a while this evening checking out the collimation with a Cheshire eyepiece. Some adjustments were necessary so I'm glad I had access to the user manuals for the other GSO RC scope variants.

And so the long wait begins for a clear night.

[johninderby]

Lovely scope

Sounds like your focuser may need some adjusting. It's actually a very good focuser and it has twice the weight handling capacity of the focuser that comes with the IKI70. Better internal build quality, although it doesn't look as nice on the outside.

John

[Revs]

That looks excellent, I look forward to seeing some images. GSO optics are good and the tube looks to be nicely over-sized. Lovely CF tube, too!

[r3i]

Lovely scope

Sounds like your focuser may need some adjusting. It's actually a very good focuser and it has twice the weight handling capacity of the focuser that comes with the IKI70. Better internal build quality, although it doesn't look as nice on the outside.

John

Hi John,

I think you've hit the nail on the head when you say it doesn't look as nice on the outside. Never judge a book by its cover.

[r3i]

Managed to get first light earlier than expected, as the skies cleared somewhat last night - it wasn't crystal clear, quite a bit of moisture in the atmosphere, but worth getting everything set up. I noticed by the end of the session heavy dew had accumulated on the outside of the tube - internally, the primary mirror was clear but the secondary had dewed up so in future I'll need to remember to use at least a dew shield.

I managed to shoot off 12*5 minute subs of NGC6888 using the QHY8 and guided using the DSI and an Orion OAG on my EQ6. This is the result, it's a full chip shot with some quick and dirty levels, curves & colour adjustment. No darks or flats.

Clearly some further collimation required in the image train as there's more curvature at the left hand side and there's quite a lot of skyglow, probably not helped by the dewing up of the secondary. However, this is a much better result across the whole field of view than I've managed to achieve through the SCT so I'm encouraged.

As per John's suggestion I adjusted the tensioning on the focuser and with a proper payload, it was nice and smooth and held everything in place.

Early days and lots to learn but so far very happy with the new scope. I would imagine that in more experienced hands it could turn out some nice images.

[swag72]

I'm really interested in seeing the results with thiss cope as I understand that with aperture being so important, this was not an ideal imaging scope, despite being marketed otherwise.

Well, that's what I thought anyway!

[kookoo_gr]

enjoy your new telescope. i have a question for you though. i have the gso rc 8'' (it's the same telescope only the brand name changes) along with a TS Off Axis Guider - 27mm and is giving me hard time finding a suitable guide star with my qhy-5. with your dsi do you find it difficult to find a guide star?

[r3i]

enjoy your new telescope. i have a question for you though. i have the gso rc 8'' (it's the same telescope only the brand name changes) along with a TS Off Axis Guider - 27mm and is giving me hard time finding a suitable guide star with my qhy-5. with your dsi do you find it difficult to find a guide star?

Hi kookoo,

Think I must've got lucky last night.

Prior to getting the RC I used a separate guidescope with my SCT, but I'm waiting for some new guidescope rings to arrive so currently I don't have a means of mounting the guidescope (my SCT has an ADM MDS rail whereas the RC has a Vixen dovetail on top).

I've had the Orion OAG for quite a while but had never got around to using it - last night provided an ideal opportunity to try it out. After a short period of trial and error I managed to get both imager and guide cameras in focus. I used PHD to guide with an exposure time of 2 seconds - there just happened to be a brightish star in the DSI's field of view.

Following this successful first run, I plan to use the OAG again- time will tell if my luck holds out.

[r3i]

Got a clear night mid week so was able to have second light. This time I tried M92. 10*5min subs with QHY8, PHD Guiding via Orion OAG + Meade DSI1. Still some curvature to fix, which is due to the CCD in my QHY8 not being orthogonal and have yet to get it adjusted out.

[Deneb]

Very nice scope, Im pondering over a 6" version myself...

Nadeem.

[Coco]

Very nice scope, Im pondering over a 6" version myself...

Nadeem.

Ditto... @400 quid it looks a bargain

[swag72]

Ditto... @400 quid it looks a bargain

But isn't it just too slow for imaging? I keep reading about aperture, surely this kind of scope flies in the face of that? Aren't we always wanting to speed our imaging scopes up?

Sorry to hijack the thread, but just very interested in this scope.

[Deneb]

Maybe slow but not impossible, I use to image with a C100ED @ f/9.

[ollypenrice]

I'm really interested in seeing the results with thiss cope as I understand that with aperture being so important, this was not an ideal imaging scope, despite being marketed otherwise.

Well, that's what I thought anyway!

The scope is a pure astrograph with too much contrast-eating central obstruction for good visual performance. The F ratio is slow, which is a drawback, but F8 is bearable. For galaxy hunting on a fairly budget mount like the EQ6 this is a good bet on paper.

I only say 'on paper' because I haven't tried one yet.

Olly