Skywatcher ST80 shorty refractor - first impressions

[Kenny_10_Bellys]

I decided it was time to get serious about my astronomy, and maybe even attempt a little imaging as well. I now own a CPC-800 which can be capable of quite accurate tracking, but as no scope can do everything I thought it best to get a small widefield scope to piggy back. I own an Orion ED80, but due to the oversized tube it's just too large and heavy to safely mount on the 8" CPC, hence my decision to purchase the ST-80.

Thanks to FLO I got my new scope delivered in a couple of day direct from the importers. Two spotty youths hauled the single box up to my flat, making it look like hard work. I had no idea it would be that heavy, even with the EQ1 tripod packaged with it. Turns out they were just feeble, it wasn't heavy at all and I lifted the lot with one hand. Panic over. It was double-boxed for safety, and all the elements included similarly seperately boxed and padded out, so no harm came to it during delivery. As well as the scope I also got the finder, EQ1 tripod & mount, rings, counterweight, 1.25" diagonal, 2X barlow and 2 eyepieces. Set up was pretty easy, it's not rocket science after all, and I was soon admiring my new purchase.

The finished article in all its tiny glory

After working with scopes ranging in price from £700 to £1900 it was a bit of an eye-opener to get a £130 scope and mount. Cheap, in the good way as well as the bad way. The scope itself is tiny, 80mm aperture and 400mm focal length make it incredibly compact and ideal for my purposes as a piggyback guidescope. It's the standard Skywatcher blue colour and seemed pretty well put together, with a good weight to it and sturdy metal screws very evident. Certainly up until I tried to pull the front lenscap off anyway, and removed the entire dewcap assembly with it. The cap is air-tight, I cant get the blumming thing off without removing major components, so i have to leave it barely on until I re-affix the dew shield somehow.

Is it meant to do that? D'oh!

Carrying on regardless, I set it up and pointed it at a few terrestrial targets and tried out the lenses and controls. They optics were surprisingly good for so cheap a scope, being both bright and sharp, but with the evident colour abberations you'd expect from bright targets in a non-APO scope. Later observations of the moon with the appropriate moon filter showed no obvious colour fringing, so I imagine that only the brightest of targets would be annoying in this way. The eyepieces and barlow supplied were on the cheap side too, but I was pleasantly surprised by the larger of the two. The 10mm however suffered from being built to a tiny price, and had practically no eye relief at all. Even the finderscope had a good, bright view and was easy to set up and align. The focus unit is a basic rack & pinion unit coated with a clear grease similar in consistency to the stuff they stick CDs to magazines with, but does have a direct mount T-ring thread and a focus locking screw for imaging.

A word about the EQ1 mount bundled with it. That word is Rubbish. For people used to CG-5s and the like it feels like a toy when you unwrap it, and it performs as well as any toy. Mounted on its spindly camera-style tripod it's as steady as a new-born foal, shaking like a leaf if you go anywhere near it. The rings are so close together on the short OTA and, thanks to some large screwheads at the rear, impossible to set up so the scope is in balance. You'd have to wrap some counterweight to the dew-shield (the bit that breaks off) or discard the rear ring. The RA and DEC controls are on bendy sticks to try and isolate the user from the vibrating mount. I dont know if this is to stop you shaking it or to stop you from getting vibrating white finger from the mount, and I look forward to throwing it all away when my piggy-back rings arrive.

In short, it's a scope built to a price. Fortunately most of it seems to have been spent on the OTA and not the accessories, and I can see why it's so popular as a guidescope and widefield addition to larger units. It's a fast lens with a great field of view and characteristics which lend themselves to imaging work. At barely a foot long it's half the size and weight of my ED80, but of course comes without the flourite lenses and crayford focuser. I look forward to getting it out at the next club night and seeing how it performs on targets like The Plieades and M42, and I'm gagging to get it mounted on my CPC. I'll let you know how I get on as and when I use it in anger.

[Kaptain Klevtsov]

Good report Kenny, but you were a bit too kind about the EQ1.

The ST80 is a cracking OTA for the price, once you get it bolted on to your main 'scope it will surprise you.

Kaptain Klevtsov

[jcm]

Yep , the ST80 is a good guide scope. Its light weight makes it ideal to piggy back on the main scope. The only feature I don't like is the rather stiff focuser ( or is it just mine ? ) this makes getting nice tight guide stars a bit fiddly as getting the exact focus is a bit hit and miss.

John

[Kenny_10_Bellys]

i think the problem with the focus is more the fault of the glue they used as grease. I plan to try and clean out the focus assembly and replace it with some more appropriately lightweight grease, and hopefully it'll make it sweet to use. When I first got the thing unwrapped I accidentally touched the focus rack underneath the tube without noticing and I've still go sticky fingers today. Nasty stuff.

KK, I hope it's as much of a surprise at first light as the ED80 was, it's amazing what these little scopes can see in the right conditions. No scope can do everything, so I think a little widefield item strapped to a lightbucket gives the best combination you can buy.

[centroid]

I used an ST80 'piggy backed' on my LX as guide scope, for some time, and it did a very good job.

As has been said, small and light.

I only changed it for an ED80, when I wanted an 80mm scope that would suit both imaging and guiding.

Dave

[brympton]

Certainly up until I tried to pull the front lenscap off anyway, and removed the entire dewcap assembly with it. The cap is air-tight, I cant get the blumming thing off without removing major components, so i have to leave it barely on until I re-affix the dew shield somehow.

...they're all like that Sir

Funny reading this review as I've only just received my ST80/QHYCCD5/Tube Rings and extender from Bernard at Modern Astronomy...all delivered free of charge, on the specified day exactly as promised.

I new it would have to be disassembled to remove the "earwax" from the focuser as I had to do this with my 250px also! The dew shield is supposed to be removable for lens cleaning but an extra piece of Velcro opposite the bit they supply takes care of things. I will say the finish inside your dew shield looks a bit rough compared to mine

...forgot to add, it's all still teriffic value for money...except the EQ1, you'd be much better off with the alt/az tripod or paying the extra (IMHO) for the STARTRAVEL 80-AUTO shown here:

http://www.opticalvision.co.uk/astronomical_telescopes/sky-watcher/short_tube_refractors

[Kenny_10_Bellys]

I mailed Bern yesterda about what I'll need to get the thing piggy-backed and what adaptors and cameras he would recommend, he's going to get back to me with a startling price and I'll have to go hungry once again to feed my dream of imaging. It's amazing the things guys would have rather than money.

When I clean the smeg out of the focus system I might take a hack-saw to the edge of the lenscap, make a few notches in the lip that holds on to the dew-sheild. Hopefully it'll make it a little less grippy if it's got some movement in it. I dont know about fitting more velcro inside, the only stuff I have is tape and it'd never fit in such a tight fit.

[lunator]

Ken

Nice report.

It sounds like the plan is coming together well

Looking forward to seeing the images soon

Cheers

Ian

[brympton]

I dont know about fitting more velcro inside, the only stuff I have is tape and it'd never fit in such a tight fit.

Not both parts, just one part (self adhesive) to improve the interference fit. Maybe yours is a tighter fit than mine with the extra paint on the inside?

I certainly wouldn't want to take a hacksaw to the lens cap ...just sand the inside rim with some emery tape and finish with scothbrite.

[Kenny_10_Bellys]

SOunds like a lot of work to me, sanding and so forth. A couple of notches in the flange of the lenscap should make it that little more flexible so it doesn't grip like superglue. Mine is a tight fit, I could probably get away with some masking tape or similar to bulk out the fit of the dewshield and make it tighter.

Lunator, I hope I'm able to get some images at the end of this, I'm gagging to get the kit and try it out.

[Kenny_10_Bellys]

Just a quick follow-up after getting my first decent look through the ST-80 at an observing session.

At the time the moon was at 60% full so it rather dominated the skies and was naturally our main target. It rose around 10pm and climbed through some trees, and as we followed its climb the ST-80 showed surprisingly sharp views, picking out every pine needle on the branches in front of the moon. As the moon cleared the trees we got our first proper view, and were rewarded with a very pleasing site through the little scope. Despite filling the eyepiece with its glaring light you had to look hard to find any chromatic aberration, with just the merest fringe of colour around the edges. Everyone who looked through the eyepiece commented on this, as well as the crispness of the view through the 80mm. It's sharp, it's clear, it's tiny and should prove a very able guide-scope and wide field instrument. For the money, its a steal.

[lunator]

Ken

Sounds like you made the right choice

Looking forward to the pics you get with the set up

Cheers

Ian

[Albireo380]

Just a quick follow-up after getting my first decent look through the ST-80 at an observing session.

At the time the moon was at 60% full so it rather dominated the skies and was naturally our main target. It rose around 10pm and climbed through some trees, and as we followed its climb the ST-80 showed surprisingly sharp views, picking out every pine needle on the branches in front of the moon. As the moon cleared the trees we got our first proper view, and were rewarded with a very pleasing site through the little scope. Despite filling the eyepiece with its glaring light you had to look hard to find any chromatic aberration, with just the merest fringe of colour around the edges. Everyone who looked through the eyepiece commented on this, as well as the crispness of the view through the 80mm. It's sharp, it's clear, it's tiny and should prove a very able guide-scope and wide field instrument. For the money, its a steal.

I would second what Kenny says (as one of the people at that moonlit observing session). A lovely little 'scope - it will be a good wide field instrument and guider. Once Kenny has it on his CPC800 he will have a great combo.

Tom

[Kenny_10_Bellys]

Well, I get my frst wage from my new job in a couple of weeks and the first thing I'll be doing is mailing Bern to order the mounts to piggyback the ST-80 to the CPC-800. I can then start using it with my DSLR for some basic imaging, and over the next few months Bern will be supplying me with an Atik 16ic and various reducers, pipework, adaptors, scaffolding, etc to get the CCD imaging and guiding on the go. I better have a picture to shoe at the end of all this or it will just be the worlds most expensive tripod.