Scope for travel / grab-and-go

[MAN or ASTROMAN]

I must admit that I'm a paid up of the Frac. club at present [removed word].

There are some very tasty 100-127mm refractors out there at present-just look at some of the beauties in the 'Show us your Frac' thread!

 I'm also a member of the TAL 100 fan club,which has a strong following here on SGL.

And rightly so-it is a marvelous bit of kit to be had for £235 new,and at F10,CA is almost non existant,to my  aging eyes at least.

[happy-kat]

The ST102 ordered I think will be really nice, it has a 2 inch focuser but worth checking if that is correct.

[spaceboy]

They have a 2" focuser but I think they come supplied with a 1.25" diagonal as standard.

The AZ4 does indeed look good. I'll see how I get on with the bundled AZ3 before I think about upgrading though!

An ST102 works OK on an AZ3 but you need to make some sort of counter weight as looking at anything above 70° you'll find the eyepiece just wants to go south. I had a couple AZ3's and they are great for solar observing where you don't tend to look at the sun when it's high over head in the blazing hot midday but I struggled no end with it trying to find high objects at night. The trouble is you have to tighten the ALT bolt with a wrench to set the friction to stop droop but if you do it too much to can't easily and precisely make coarse movements to targets before then using the slow motion controls. While the AZ4 isn't perfect it is a massive improvement over the AZ3 and well worth the cost new  http://www.firstlightoptics.com/alt-azimuth/skywatcher-az4-alt-az-mount.html and even more so if you can pick one up used (£90-£110 depending on condition and tripod)

[DevonSkies]

...and my Startravel 102T arrived this morning! Already assembled it and briefly testing it with some terrestrial viewing. All feels sturdy and nicely put together. It's a sunny day here, so there's plenty of CA visible in high magnification terrestrial views, but that is to be expected. I'm hoping the clear skies will persist until tonight for a proper astro test, but I don't hold out much hope!

Mine came with a 45deg erecting prism (standard with the AZ3 mount). Can anyone suggest a decent star diagonal (preferably 2")? Ideally around the £50 mark, but could go higher if need be.

[spaceboy]

http://www.firstlightoptics.com/diagonals/skywatcher-di-electric-star-diagonal.html I think is your cheapest Di-electric option unless you put a wanted advert up for a used one in the classified section.

[DevonSkies]

So I've spent some time over Christmas playing with the ST102 (including one clear night under the stars) and unfortunately I've been disappointed with the build quality of it. Maybe I was expecting too much from such a cheap scope, but issues with the sloppy rack-and-pinion focus tube and poorly aligned focuser assembly have destroyed my confidence in this scope. The sticky grease oozing from the focus rack is horrible, and tightening the focuser tension screws, whilst removing the slop, makes the focuser unacceptably tight. I hear much of this can be remedied by stripping down the focuser, but there's no way I'm going to that trouble on a brand new scope. One of the screws holding the focuser in place was also loose, resulting in misalignment. So, it's going back for a refund in the new year. I know many are happy with these scopes, so maybe I'm just fussy, but this one isn't for me. I'm gutted, as I can't fault my other Skywatcher scope (the 250PX).

So it looks like my search for a travel scope continues! Maybe the Heritage 130P would suit me better after all, since I'm happy with my big Dob.

[Alfian]

Sorry to hear about the thumbs down on the ST102. Given your issues with its focuser  I'm not sure how the 130P would suit you. It has a very simple helical focuser which tends to feel loose in operation. This can be easily and quite effectively improved with a few winds of PTFE tape. Initially it really spoiled it for me, a constant irritation. I spent a lot of time wondering how it could be replaced, but eventually realising it would involve irreversible surgery and probably cost more than it was worth, gave up on the idea. Since then thogh I've kind of revised my opinion of the scope. Despite its shortcomings the focuser does work sufficiently well. The scope's compact design (which I love) and particularly its surprisingly good optical qualities, make it a very useful little scope. The mini-dob mount is very simple but works, again, sufficiently well.  So, if you can live with focuser, all well and good. IF. 

If on the other hand you still fancy a short tube refractor as a grab 'n go (with a decent focuser) what about this one:

http://www.opticstar.com/Run/Astronomy/Astro-Telescopes-Opticstar.asp?p=0_10_1_1_64

[Paul73]

Sorry to hear that it didn't work out. I have a second hand SW ED80 on a modified AZ3 for a grab & go.

On the plus side:

- good build quality

- cracking optics for the cash

- lovely wide fields (NA nebula is better in this than my 10"!)

- great rugged carry case if you get that version.

- Great for solar with a wedge

On the down side:

- Needs an Az4

- After my 10". Everything seems rather dim at first

- the focuser can need a bit of adjustment on some scopes.

- never going to be a DSO marvel.

I am a big fan. But wish that I had gone for the ED100......

Paul

[Mark at Beaufort]

If I was buying a scope for grab and go and taking on holiday I would buy a short quality refractor. I had a William Optics SD66 (regret selling) and I had fantastic views of many DSOs including the North American Neb and Messier 101.

This is an example of what I would prefer -

http://www.altairastro.com/lightwave-66mm-f6-ed-r-refractor-with-dual-speed-r-p-focuser-alu-case.html

or

http://www.altairastro.com/lightwave-72mm-f6-ed-refractor-with-dual-speed-r-p-focuser-alu-case.html

I have a pair of Helios Apollo 15x70 binos which I have found to be fantastic - so this is another option.

[DevonSkies]

Sorry to hear about the thumbs down on the ST102. Given your issues with its focuser  I'm not sure how the 130P would suit you. It has a very simple helical focuser which tends to feel loose in operation. This can be easily and quite effectively improved with a few winds of PTFE tape. Initially it really spoiled it for me, a constant irritation. I spent a lot of time wondering how it could be replaced, but eventually realising it would involve irreversible surgery and probably cost more than it was worth, gave up on the idea. Since then thogh I've kind of revised my opinion of the scope. Despite its shortcomings the focuser does work sufficiently well. The scope's compact design (which I love) and particularly its surprisingly good optical qualities, make it a very useful little scope. The mini-dob mount is very simple but works, again, sufficiently well.  So, if you can live with focuser, all well and good. IF. 

If on the other hand you still fancy a short tube refractor as a grab 'n go (with a decent focuser) what about this one:

http://www.opticstar.com/Run/Astronomy/Astro-Telescopes-Opticstar.asp?p=0_10_1_1_64

Thanks for the advice. I note what you say about the focuser on the 130P. How do you feel about the robustness of the 130P for travel? Is it preferable to separate the mount, or can it be packed well as a single unit? I initially discounted it because I thought I refractor would be more robust and need no adjustment in the field, but having said that I am quite comfortable with collimating a Newtonian (having tweaked my 250PX a few times). I am also attracted by a small Newtonian because of the lack of colour fringing, compared to the CA inherent in the achromatic ST102 refractor.

I'll also take a look at the Opticstar frac you mentioned. Thanks.

[Moonshane]

My advice for the stated purpose is save a bit longer and get a 80mm ed with an az4. Buy used and you'll get setup for about £300

[DevonSkies]

Thanks Alfian, Paul and Mark.

I still like the idea of a short-tube refractor, so I will certainly consider a better quality model, maybe even an ED if not too expensive (the Lightwave ones could be in my budget, but are smaller than what I was originally looking for).

Any other suggestions for short-tube refractors would be very welcome! Ideally in the 80-100mm range.

Ed

[Mark at Beaufort]

Ed I have an Astro Tech ED Refractor which is excellent - focal length is 709mm and is f6.95. However, although its great on the SkyTee 2 mount I would not take it on holiday - I have a canal boat and only ever take binoculars.

This is why I recommended a small quality APO/ED frac. So if you really want a slightly larger frac then perhaps something like this might be better - http://www.firstlightoptics.com/pro-series/skywatcher-evostar-80ed-ds-pro-ota.html

I attach a photo (a few years old) which shows my 4" frac against the William Optics 66mm frac.

[DevonSkies]

Ed I have an Astro Tech ED Refractor which is excellent - focal length is 709mm and is f6.95. However, although its great on the SkyTee 2 mount I would not take it on holiday - I have a canal boat and only ever take binoculars.

This is why I recommended a small quality APO/ED frac. So if you really want a slightly larger frac then perhaps something like this might be better - http://www.firstlightoptics.com/pro-series/skywatcher-evostar-80ed-ds-pro-ota.html

Thanks. Always good to see a picture!

I think you're right - a smaller ED scope (70-80mm) would be ideal for holidays. Although I was hankering after more light grasp, the larger scopes will be harder to transport (I still have the SW102 in the house and it won't fit in a small flight case without removing the dew shield, which is jammed on pretty tightly!).

[Alfian]

Though not as rugged as a refractor, the Heritage 130P is pretty robust. In the closed up position and adjusted on the long dovetail the OTA sits vertically (like a mini light bucket) on the dob mount and is very easy to carry around. Collimation is about as easy as it gets but it holds its collimation well any way. The Dob mount does need to be sat on something stable of the right height, At home I use it on a wrought iron garden table, but it has also been on the bonnet of the car - not ideal but it works!  I've found that the mini-Dob mount will also take my Mak 102 very well which makes for a very portable little package.

[happy-kat]

Have used my dslr and have used a small mak and have used a refractor on the mount. I got the camera adaptor dove bar for my heritage base as all my other stuff uses a camera thread.

I sit mine on an upturned bucket.

[Alfian]

I've used the similar adapter on my AZ4. It had not occurred to me to use it on the Heritage, thanks!

[DevonSkies]

After some thought, I'm giving the ST102 another chance. I still think this telescope is phenomenal value for money for a 102mm objective (£183 including the AZ3 mount!). If I can make it work for me then it will be money well spent. After all, it's only meant to be a secondary setup for holidays/grab-and-go.

So, not to be beaten, I've had another fiddle with the scope. I've managed to nicely square the focus drawtube by tightening the front grub screw (furthest from the eyepiece), and then removed most of the 'rocking' from the focuser by tightening down the rear grub screw just enough. Since these screws weren't tightened at the factory, the friction on the focuser is increased, but it is still reasonably smooth. I then spent quite some time aligning the whole focuser using my Cheshire eyepiece, wiggling the focuser assembly to align the reflected circles and crosshairs as precisely as possible and tightening down the mounting screws until I was satisfied it was as close as I could get it. I actually repeated this procedure several times until I was convinced I couldn't improve it any more. There is still a slight up/down misalignment (possibly an offset rather than a tilt, which can't be corrected), but maybe it is close enough. Finally, I have got hold of a nice 2" dielectric quartz diagonal to replace the cheap 45deg prism.

The real test will of course be a night under the stars. I'm hoping the forecast for clear skies on Thursday night comes true, so I can put it through its paces again. If anyone's interested, I'll report back afterwards!

Ed

[happy-kat]

Yes please to read your next report.

[DevonSkies]

So I pulled the curtains apart before heading for bed at midnight tonight and was surprised to see a sparkling clear sky! Well, the ST102 is supposed to be a grab-and-go, so I grabbed, and I went!

I only managed 20 minutes outside before the clouds rolled in and it started to rain, but what I saw was very encouraging. My tweaks seem to have paid off. A star test on Sirius at 100x showed symmetrical rings either side of focus, indicating that after my adjustments the collimation is now more than good enough for a wide-field scope. I was able to easily split Castor at 100x using my BST 5mm EP. Jupiter was visible but low in the sky, and was a clear disc at 100x with cloud bands just about visible. CA was present, but not objectionable. The moon was clear and crisp, although still too low in the sky for good seeing. I did clearly notice that the CA is much reduced with the new dielectric diagonal compared to the original 45-degree prism. All in all, a big improvement over my first experience of this scope!

I did experience problems with the AZ3 mount drooping at high elevations, especially with the weight of the 2" diagonal attached. I think an AZ4 will be on my shopping list soon.

Tomorrow evening I hope to do a more extensive test before the moon comes up, and post an update.

Ed

[happy-kat]

Sounds good observing report.

I think I gave a link previously on adding a counter weight to the az3 to sort out the drooping on elevation, particularly if you like the slowmo controls which are lost on the az4.