Louis D

16 minutes ago, johninderby said:

The rigel finder comes with a mounting plate that can be stuck down with the provided foam tape but I find it often falls off. You can stick the mounting plate down with silicone sealer for a more secure mounting. There is a screw hole in the plate so it can also be bolted down.

My QF mounting plate has been stuck down to my Dob's tube for well over a decade now and shows no signs of coming off, so I guess it just depends.

As far as adapting the ES finder shoe to a Synta/Vixen mount, there is this option and this one.

There are also adapters from ES to QF and Synta/Vixen to QF.  You don't need to drill new holes if you have the money to buy adapters.

If you can get all the way south to Jad Al Jamal, you might have decently dark skies, especially to the south, which is the best direction to have consistently dark skies.

I use a TSFLAT2 visually in my AT72ED and TS-Optics 90mm APO Triplet.  It works wonders to flatten the field without changing the focal length.  It does have a pretty long back focal distance to accommodate either a 2" diagonal or a filter wheel or an off axis guider.  It comes with a M48 thread on each end.

Here's a couple of photos taken with it on their webpage:

You're never going to see galaxies from a heavily light polluted area.  If your night skies are washed out and relatively few stars are visible, solar system objects and some star clusters and double stars will be your main targets.

An 80mm f/5 refractor is generally referred to as an ST80 meaning a Short Tube 80mm.  They have loads of chromatic aberration and spherical aberration.  They're only useful up to about 60x, so that rules out using them for solar system objects aside from the moon.  These are fine for travel, spotting scope duty, and low power scanning of star fields.  I have had one for 20 years and rarely use it because it doesn't do anything particularly well except white light solar with a proper front mounted solar filter.

An 80mm f/11.2 refractor would be much better for general astronomy.  Much less chromatic aberration and practically no spherical aberration.  The computerized mount might come in handy in light polluted skies to find dim objects, assuming you can see enough bright stars to align it in the first place.  The 900mm focal length is just about ideal for beginner astronomy as well.

Having had a look at the 12mm to 15mm eyepieces at those shops, the 12mm BST Starguider (Paradigm, etc) would probably be your best bet for usability and quality at your price point.  Most of the rest are either Plossl or even simpler designs or are Konig/Erfle variants which don't do well at f/5.  Prices in general are definitely higher than in the US.  Part of it is 20% VAT is included in the advertised prices whereas US state/local sales taxes are added in later.  I noticed some don't remove the VAT when shipping to the US which is incorrect.

1 hour ago, Frostak said:

Thank you for the explanation. I will get the GSO then, 10€ is not such a big deal. I also managed to get Celestron x-cel 7mm for a fairly good price, from what I've read they should be pretty decent.
So I guess I just need to figure out a 12-15mm EP and I should be good to go. Would you happen to have a recommendation in that range? I was looking at the BST 12mm which looked promising, but it's not really worth paying high shipment cost for delivery from England.

As long as that's an X-Cel LX and not the original X-Cel, you should be okay.  The LX is similar to the Meade HD-60 while the X-Cel have loads of spherical aberration of the exit pupil (SAEP).

Eye relief is going to get tight with a 12mm Plossl at around 8mm if the eye lens is mounted near the top, less if recessed.

What are your preferred astro vendors in Slovakia?  It would help to know what is available at a reasonable cost to you.

Below are my 12mm to 15mm eyepieces to give you some idea of the range of options available if your budget permits.

4 hours ago, Deltox said:

Should I rather look for a newtonian reflector with an EQ mount, or just give up my basic AP wish and go for a dobsonian that doesn't track? Some people have suggested to drop AP for now and go for the dob, is there a possibilty to upgrade later to make the dob work for AP, like putting it on an EQ mount, or would I have to buy a new telescope again?

You could go with a dual axis equatorial platform to put under a Dob later for basic astrophotography.

47 minutes ago, Frostak said:

@Louis D Between the GSO (apparently marketed here as TS, though I'm able to get GSO as well) and the Orion Sirius which one would you recommend? I'm able to get the Orion for about 10€ cheaper.

On the image it seems the Orion has a slightly better defined edges. Also do you happen to know if these would perform decently on f/5 scope? I'm sure it would be a step up from what I have currently but doesn't hurt to ask.
And for the highest focal lenght eyepiece is the 32mm the better choice? Before I was thinking more of getting something around 25mm considering my scope has fairly short focal length (650mm).

EDIT: I noticed now that the GSO is FMC where as Orion is only MC. Not sure how much of a difference that makes.

The Orion Sirius is single coated, at least the late 90s vintage I have.  It just reflects a pale purple indicative of MgF2.  The GSO are beautifully multicoated resulting in all sorts of deeply saturated color reflections more in line with premium eyepieces like Pentax XWs and Vixen SLVs.  The GSO gives nice dark backgrounds, low scatter, saturated star colors, etc.  I'd say the GSO is better corrected to the edge.  Notice in my photo how the Sirius at the top gets less distinct toward the edges while the GSO directly below it remains pretty much sharp to the edge.  Color saturation is stronger as well in the GSO.  It has a distinct and sharp field stop despite the fuzziness on the left that was most likely due to a slight misalignment of the camera lens with the eyepiece exit pupil.  The GSO is definitely worth the 10€ upcharge.  The 25mm BST and the 32mm Plossl will yield roughly the same true field of view (TFOV) on the sky owing to the former's wider apparent field of view (AFOV).  The Plossl will look sharper across the field while the BST will get fuzzy in the outer 50%.  Personally, I prefer a sharper, lower power image to a fuzzier, higher power image.

The 32mm GSO/Revelation Plossl is also very good as a lowest power 1.25" eyepiece as well as being fairly inexpensive.  It's the second one below.

I did a comparative review of the BSTs (Paradigms) vs Meade HD-60s.  They're good, especially the shorter focal lengths.  The 25mm would be the one most likely to suffer at f/5 since it's already struggling at f/6.  Don't forget that our site sponsor, FLO, offers a 10% discount on 2, 15% discount on 4, and 20% discount on 7 BST Starguiders.  I have no experience with the BST Barlow.  I would watch for a used Meade 140 2x Barlow to come up for about $40.  They are a Japanese made triplet design of the 1990s that perform just as well as the Televue 2x Barlow (which I also have).

4 hours ago, Heywood Floyd said:

Thanks for all the info. I found the label and it says 500mm so it's a 1145p, google seems to confirm. I'll do some research into it then decide what to do, scouts is a good idea. Appreciate the help. 

 

Then it has a parabolic mirror and is a standard Newtonian design, so it should perform optically pretty well.

2 hours ago, MarkAR said:

Wouldn't be this, he eyepiece definitely has one focus point for the stars and another for the crosshairs.

Oh, I think I see now.  The reticle etching isn't in the same plane as the field stop/focal plane.  I agree that it sounds like the factory installed the reticle upside-down.

47 minutes ago, nutrocker said:

Thanks for all your inputs.In a nutshell when the crosshairs are finely focused the eye piece is just slightly out. there is no more travel left. There seems to be no way around this. I think i am going to ask Altair to send me a replacement EP and take it from there.

Do you need to wear eyeglasses?  Perhaps try focusing the crosshairs while wearing glasses to see if you've reached the diopter limit of it's built-in focuser.

2 hours ago, Filroden said:

So any planet, whether an inferior or exterior, can be see at midnight at very high latitudes during winter because it's also possible to see the Sun at midnight at those latitudes!

I think the BBC have over simplified something to the point that it's now actually more confusing.

Which goes to prove that given the right circumstances, just about anything is possible.  I suppose if a small black hole or group of them wandered into the inner solar system, it or they could make Venus visible at midnight on the meridian given the proper alignment to warp space-time just right.  I don't think I'd want to be around to witness it, though.

51 minutes ago, bomberbaz said:

I do have astigmatism but find that once the exit pupil is less than 3mm it no longer causes a serious issue, therefore I do without my glasses. 

I have found this out after a long time of ignoring many eyepieces due to low eye relief, now I know better. You should try higher powered EP without your glasses, you may be surprised.

Anyway, I have ordered the OVL as it offers all I require of it at the right price.

Thanks to all for their input, much obliged as always.

Steve

I have 2 diopters of astigmatism, and I can indeed get away without using eyeglasses at sub-1mm exit pupils, but there is still some minor improvement even then when I swap in my eyeglasses.  Once I get below 0.7mm exit pupil, floaters become a huge issue for me, so I have a narrow window of opportunity not to wear eyeglasses.  According to TV's Dioptrx chart below, you must have about 0.75x diopters of astigmatism.

23 minutes ago, Nicola Hannah Butterfield said:

If Stellarium is right 31/5/2023 Venus is 5°39'41" degrees above the horizon at midnight from my location, though it's still not opposition.

It is possible that at greatest elongation and at high observing latitudes, it is possible for Venus to be visible many hours after sunset (or hours before sunrise).  However, it will never be on the meridian at astronomical midnight like a superior planet at opposition.

Here's an assembly video I found.  Try reversing the steps by loosening the accessory tray and then the long chromed rod to free the mount head.  If the rod is stuck, you might need a wrench (spanner?) to free it.

19 minutes ago, Steve Clay said:

The OVL zoom is reall good.

Unless you need to wear eyeglasses at the eyepiece due to strong astigmatism.  I measured mine to have between 9mm and 11mm of usable eye relief making the already narrow AFOV (33 to 49 degrees) even narrower.

6 hours ago, Waldemar said:

Laser may be a nice tool for the one who is using it, but for the rest of us it is light pollution... 

It is nearly impossible to make it out further than about 20 feet off axis unless there's a lot of dust/moisture in the air, and I wouldn't be observing under those conditions anyway.  I definitely wouldn't recommend them if there are astrophotographers nearby as at a star party because they will pick them up in their images, but from a backyard by yourself, it is negligible.  I just can't bend around to look up through an RDF style finder anymore, nor can I merge the images of the sky and RDF with my bifocals.

6 hours ago, Beardy30 said:

It’s a SKYHAWK 114 

Does that make it a Jones-Bird/Bird-Jones design then?

From the FLO description:

Fitted with a Synta-style finder shoe

I've always heard that style fitting described as a Vixen-style finder shoe.  When did the nomenclature change?

8 hours ago, Ricochet said:

The red dot is only visible on the screen of the RDF. It is not a laser and cannot be see through the telescope. The trick is simply to get what you are looking at to also appear to be behind the red dot when you view from behind the finder. 

Correct, a laser sight is visible in the eyepiece where an RDF is not.  That the laser beam is visible makes alignment at night really easy by aiming the scope at a bright star using the laser as a rough starting point.  You then center the star in the scope and align the laser close to the star and then look in the eyepiece and center the end of the laser beam in the eyepiece.  Of course, laser sights are discouraged in the UK despite being popular in the US.

The difference between my Astro Tech 72ED and my ST80 is huge.  No star bloating, no spherical aberration, no violet color below 100x and very mild above that in the 72ED.  It has an excellent focuser except that it slips with loads above 2 pounds at high inclinations no matter how much I tighten the tension and rough up the flat of the tube.  I was pleased enough I moved up to a 90mm TS Optics APO triplet after 6 years.  It's definitely better, especially the focuser, but the difference between the FPL-51 doublet in the 72ED and the FPL-53 triplet in the 90mm isn't nearly as much as the difference between the achromatic doublet and the FPL-51 doublet.

The AT72ED does not quite have enough in-travel for binoviewers, but might have enough for advanced solar usage.  It has about 8cm of travel with the default focus position about in the middle with a 1.25" diagonal.  It is annoying that the focuser won't accept a 2" diagonal nosepiece further than about an inch or so.  With the dew shield retracted and the focuser racked all the way in, it is very compact.

I would expect the optical performance of the SW72ED to be similar to the AT72ED, but with different mechanicals.  It is definitely worthwhile to step up to an ED scope.

I took my Celestron Regal 8-24mm zoom to Nebraska to view the partial and total phases of the 2017 eclipse in my ST80.  It worked really well for both.  It's also sold with Olivon spotting scopes.

2 hours ago, vlaiv said:

That scope is not going to be considerably lighter than comparable aperture dobsonian telescope.

Mount head is 3.2kg, tripod is 3.3kg, tube weight is 5.3kg and there are at least 5kg worth of counterweights included. Fully assembled setup is going to be around 16-17kg.

That is pretty much the same as 6" dob version - which is (just checked) 5.8kg for tube and about 10kg for base - so total about 16kg.

And, any tripod based mount is going to be very top heavy if you need to pick it up and move it about fully assembled to dodge sky obstructions like trees and buildings.  It will tend to want to flop over when you pick it up.  Dobs tend to be bottom heavy, so if you can grab it by the sides near the altitude pivot and hug it close to your body and do a penguin waddle, they're pretty easy to move about to dodge obstructions.