Ricochet

48 minutes ago, adictd2dalite said:

Got it 🙂 

Great news. Just be aware that the 2" eyepiece clamp has a small hex grub screw in the side that you need to loosen before the clamp will unscrew. From memory it's either 2 or 2.5mm. 

Stick a finger in the gap and push against one end of the compression ring to slide it around so that the gap is half way between two screws. A compression ring has to be able to move so it is possible that over time it moves to a position where a screw is exposed.

1 hour ago, StuartT said:

Does low eye relief end up being uncomfortable then?

Essentially, that is it. At very low eye relief the distance is so short that your eye lashes brush the lens each time you blink, which can be off putting. Also, it seems more tiring to hold position over a low relief eyepiece than a long eye relief eyepiece with a correctly sized eye cup. Being relaxed and not tired at the eyepiece allows you to observe more detail in the object you are looking at. 

1 minute ago, StuartT said:

So are Plössl eyepieces basically entry level, economical eyepieces? A bit like the 'kit lens' on a camera?

The equivalent to the "kit lens" is probably the MA eyepieces supplied with some scopes so Plossls are a step up from that, perhaps a "good kit lens". once you get the Morpheus the most obvious differences you will see will be the wider field and the greater comfort due to the eye relief, especially compared to the 6.7mm Plossl. You might also notice the coatings are a bit better and it seems more transparent and that the stars near the edge of the field hold their shape better, although at f10 this last one might not be very obvious as f10 is kind on eyepieces. If you had an f5 scope (or get one in future) it would be very obvious.

1 hour ago, Yellow dwarf said:

Oh just to add on to my previous post I also saw Mars and Uranus when they were close together in January through the travel scope 70, so if an 8 inch dob is a significant upgrade I can’t wait to start using it.(Shame about the delays in shipping though.)

It will be a massive upgrade on all objects (except anything too large to fit into the field of view). What you can expect to see always seems like an impossible question to answer, as instead of a concrete answer all that I can really say is that you will see the same objects "better".

1 minute ago, StuartT said:

uh oh... surely you're not suggesting this is an endless process of buying newer and better toys... ?

🤣

It could be, but by starting with a 12.5mm Morpheus, you might well never need another 12.5mm eyepiece again, well, until you find out about binoviewers that is. 😉 (Although in seriousness, I think the Morpheus range might be a touch too wide for that.)

Your Plossls could well be in danger though.

1 hour ago, StuartT said:

I live in town where the sky is a bit rubbish (Bortle 6) and I don't have a car to take my scope out somewhere nice.

Any tips on any techniques to make the best of a bad situation? Maybe filters to get rid of the sodium lamps?

Thanks

It depends on the target:

• Planets - these can be observed no matter the level of light pollution. In fact a bit of light pollution might even be an advantage here as is will help preserve your colour vision. A Baader Neodymium filter can help here, but this mostly to do with increasing contrast between areas on the planets (particularly Jupiter) although it does have a bit of a dip in the spectrum where sodium lights transmit.
• Point sources; double stars, open star clusters and globular clusters that can be resolved into individual stars (i.e. M13). - For point sources the brightness is pretty much only determined by the aperture of your telescope up until you can resolve the Airy disk, while the brightness of extended objects, such as the sky, is proportional to the exit pupil of your telescope/eyepiece combination. This means that you can decrease the brightness of the sky whilst keeping the brightness of the stars almost constant by increasing the magnification. Try to observe these objects with as high a magnification as possible while keeping the object within the field of view, up to the point where the eyepiece focal length equals the f-ratio of your telescope. This equates to a 1mm exit pupil, which is generated by a 10mm eyepiece in your f10 SCT. You may find it beneficial to upgrade to eyepieces with a wider apparent field of view so that you can fit slightly larger objects into the field of view at high magnifications. The ES82° range would work well with your SCT.
• Emission nebulae - The views of emission nebulae can be improved by the use of suitable UHC and OIII filters. These will not perform miracles and you will still find that some objects are invisible, but the right filter on the right object can make a worthwhile difference. As these filters work by blocking light, they dim the image and so you need to pay attention to the exit pupil when using them.As a guide I would suggest that a UHC filter should be used with exit pupils greater than 2mm and a OIII with exit pupils greater than 3mm. I have also found that it is a false economy to buy cheap filters. The worse your light pollution, the narrower you need the bandpass of your filter to be in order to block out more of the light pollution. You may even find that a OIII filter works better for you on some objects where the prevailing opinion is that a UHC filter is better. I would suggest you look at the Astronomik filters, and the new Televue filters, which are made by Astronomik.
• Galaxies - these are broadband, extended objects so there isn't really a lot you can do to counter light pollution. Anything you do to cut the light pollution will cut the emission from the galaxy as well. In the past I have seen a small improvement on some galaxies by using an Astronomik CLS filter, but the only real option is to go somewhere darker. As LEDs become more universal the effect of a CLS will be ever more reduced, so if you see a reasonably priced second hand Astronomik CLS you could give it a go, but I probably wouldn't buy a new one.

Generally speaking there are also a couple of things that you should try to do to counter light pollution on all DSOs. The first is to try to observe the object when it is highest in the sky, and/or in a direction that is less affected by light pollution. The lower the light pollution, the greater the contrast and even this small change could be the difference between seeing an object and not seeing it. Secondly, once you have found an object, you should sit and observe it for a long time whilst darkening your immediate surroundings so that your night vision can improve. I suggest that you get a patch for your non-observing eye, have a large hood or blanket over your head and use eyepiece where the eye cup is tall enough so that your head touches it and blocks outside light. If your chosen eyepieces don't meet this criteria you could make or purchase something to help block out glare. The Spot Bandit has recently come up in discussion on these boards as FLO have started selling the Bino Bandit and could well be worth purchasing.

9 hours ago, Jasonb said:

Thanks John!

I understand exactly what you mean about the primary mirror screws, but I should have explained, that I've read about tightening the tilt screws with regard to the secondary adjustment (in the Astrobaby guide). To my mind any adjustment on those screws moves the mirror, so I don't see how tightening them after getting it perfect doesn't just ruin it again? 

If you tighten all the secondary screws equally the collimation should remain the same. The trick is to tighten the screws whilst looking through your Cheshire so that you can make sure the tightening locks the secondary in the correct position. Alternatively, you can just tighten the central screw which will pull the mirror stalk up against the collimation screws. 

Edit: Beaten to it by quite some time. When I opened the thread there were no visible posts about the secondary, when I hit reply lots loaded. 

I always used to have to collimate my dob at the start of my session, but the last time I collimated the telescope I tightened the collimation/lock screws more tightly. Since that time I've not had to recollimate my telescope. I took a photo of the collimation at the time and recently I wanted to post that photo. When I had scrolled back far enough to find it, I discovered it was taken in something like April 2019. So my advice of you are collimating at every session is to tighten everything up more securely and see if that helps the telescope hold collimation. 

31 minutes ago, Lotinsh said:

@Ricochet Hey, there are two versions of the telescope (90/900 one) there is the AZ mount for 200 and the EQ mount for 230, is it worth getting the EQ mount for 30 Eur more?

https://teleskopy.pl/product_info.php?cPath=21_33&products_id=1424&lunety=Teleskop Sky Watcher Synta R 90 900 AZ 3

https://teleskopy.pl/product_info.php?cPath=21_33&products_id=1304&lunety=Teleskop Sky Watcher Synta R 90 900 EQ 2

I've not used either of these mounts so I can't say which one is the most stable over the other, which is probably the most important factor in choosing. 

6 minutes ago, Lotinsh said:

@michael.h.f.wilkinson This also looks like a good option, though how do I get a tripod for this? It would be nice to also use it outside instead of inside as I live in the middle of city.

You don't put it on a tripod. You find some raised surface that you can place the base on so that the telescope is at a reasonable height. You can buy an alt-az astronomical tripod with a vixen dovetail clamp, like the skywatcher az4 or az5, and fit the telescope straight to that, but then you will probably exceed your budget. 

You don't need a reducer to change the focal ratio for visual astronomy, you instead change eyepieces to alter the exit pupil size and/or field of view depending on what object you are looking at. A "standard" 1200mm 6/8/10" dob is a good all round telescope choice and a good alternative instrument to your binoculars. I have both 16x70 binoculars and an 8" dob and think it is a good pairing. 

25 minutes ago, Lotinsh said:

@Ricochet Thanks, if I'm not wrong, high focal tube lenght, means it's bad for viewing nebulas? Will I be able to see nebulas and galaxies with this telescope? It seems pretty good on paper.

Only in so much as the field of view is limited by the focal length of the telescope and maximum field stop for the size eyepieces it will take. For the 90/900 with a 32mm Plossl the maximum field of view is roughly the same as for my 8" dob, so I would not be particularly worried. Getting to a dark site will be far more important for nebulae and galaxies. If you click resources (top of the page on desktop, in the menu on mobile) > astronomy tools > FoV calculator you can simulate the field of view for a telescope as different eyepieces, then click through the various Messier objects to get an idea of what fits into the field of view and what doesn't. 

Which 130 do you have? If it is a 130p with rings and a dovetail you could just buy an AZ4 mount and put your current telescope on it. 

46 minutes ago, Lotinsh said:

https://teleskopy.pl/Sky-Watcher-R-90/900-EQ-2-telescope-teleskopy-1304.html

This one is possibly the best option you have found so far. In astronomical terms the mount is still a bit on the lightweight side but it is use able and light years ahead of the mounts supplied with the telescopes you were originally looking at. The other already suggested option now you have increased your budget is the Bresser 80/640 which is a slightly smaller and more portable option on an alt/az mount whereas the skywatcher is on an equatorial mount. 

51 minutes ago, Lotinsh said:

 

https://teleskopy.pl/Bresser-Messier-AR-102-optical-tube-with-HEX-drawtube-teleskopy-3555.html

https://teleskopy.pl/Sky-Watcher-N-200/1000-(BKP200/1000)-OTAW-teleskopy-1864.html

These two are OTA items, which means Optical Tube Assembly, i.e. just the telescope and no mount. A suitable mount for either of these will exceed your budget. In fact a suitable mount for the second one will probably cost double your new increased budget on its own. 

2 hours ago, Lotinsh said:

@Ricochet Hey man, if you have some time mind explaining to me what inadequate mount and non standard fittings mean? 

 

Ok, so what I mean by fittings is how the telescope connects to the mount and also how the finder scope connects to the telescope. Have a look at the picture below, by @Highburymark of a telescope attached to a mount.

You can see a long silver bar attached to the telescope, which is a "Vixen" dovetail, and on the mount you can see a silver clamp that is holding onto the dovetail. These items are a standard size so that telescope with its standard dovetail can be fitted onto any mount that has a Vixen dovetail clamp, so you can have more than one telescope and mount and interchange them. More importantly, it means that if you buy a telescope and discover that the mount is not strong enough to hold the telescope well, you can just buy a new mount and put your telescope on it, you don't have to buy a whole new setup, or hunt for the correct size rings to enable you to put a normal dovetail on your telescope and use it with a new mount. Similarly, if you look at the focuser in the above photo, you can see a smaller black clamp rising up off the telescope. This is a standard Vixen/Synta finder shoe, and there are many different finders that use this system so you have lots of options to upgrade or replace the finder that comes with the telescope. The Starrider telescope you were first looking at did not appear to have either of these. The telescope looks like it fits to the mount with some unique system, so it is not so easy to just buy a new mount and put your telescope on it, and the finder is screwed on, which limits you to only a couple of cheap finders should the supplied one break.

With regards to the mount, it is very important that the mount and tripod are very strong and sturdy so that they can hold the telescope in the position that you are trying to point it and to not have a lot of vibration, which will prevent you from being able to actually see anything through the telescope. If you look at say https://www.firstlightoptics.com/alt-azimuth-astronomy-mounts/skywatcher-az4-alt-az-mount.html you will notice that it has a big solid mount head and thick steel legs. This would make a very sturdy mount for an ST80 type scope. If you now look back at the mount that comes with the Levenhuk, you will see that in comparison it is very small and spindly. That mount will not hold even a small telescope like the ST80 very well. You will definitely have lots of vibrations every time you go near it and you will also find that when you point the telescope up, the mount head will flop backwards so you would have to hold the handle at all times just to keep the telescope pointed in the right direction. Of the two telescopes you have said you can afford, I think I prefer the Starrider, but I think that the one suggested by @vlaiv is is probably better by more than the difference in price (even though it is out of your budget).

20 minutes ago, gary19 said:

Thinking of getting this - https://uk.telescope.com/Telescopes/Refractor-Telescopes/Refractor-Telescopes-for-Astrophotography/Orion-ED80T-CF-Triplet-Apochromatic-Refractor-Telescope/pc/1306/c/1314/sc/1342/p/109925.uts?refineByCategoryId=1342

I think this is a bit of an extravagance for a 5 and 10 year old. An 80mm carbon fibre triplet is a premium small scope mostly aimed at astrophotography. For visual a doublet is going to be lighter and will cool quicker, both of which are probably key considerations if you want to use the telescope as a grab and go instrument. 

Do you have a link to the shop you are looking at? Do they list all the out of stock telescopes too? If they only list in stock telescopes there is a chance they might have something suitable once deliveries from china start coming in more regularly (and more cheaply). 

16 minutes ago, Lotinsh said:

So I found the ST80 from my country shop around 160, but at the same price is the Levenhuk skyline travel 80, so which one should I get? 

The normal ST80. Optically they may be the same telescope, but the Levenhuk has the same problems with an inadequate mount and non-standard fittings as the first one. 

Bear in mind that the normal ST80 can be bought as an OTA only package so check the one you are looking at comes with a mount. 

59 minutes ago, Lotinsh said:

am currently looking at StarRider 80F400EQ, is it any good? 

Probably not. On face value it looks like a typical 80mm f5 achromat, which is a fairly standard scope, sold for instance as the skywatcher skytravel (ST) 80. However, the one you've linked to appears to have an even cheaper focuser than normal, with no standard finder shoe for you to easily swap finder as with the normal one. In terms of mounting, the mount itself looks extremely weak and flimsy, and the connection between telescope and mount looks like some odd concoction instead of the standard vixen dovetail/clamp so you can't easily mount the telescope on a decent mount later. Finally, it looks to have an erecting prism, which is aimed more at terrestrial use, rather than a star diagonal, so that would also need replacing. 

Personally, if I was in your position, i would buy a Skywatcher Heritage 130p. I suspect with recent price increases this is now over your budget, but I would suggest saving up until it is in your budget rather than buying something cheaper which turns out to be a waste of money. With current global stock issues I suspect that you will have to wait for a telescope anyway so saving up longer may not be as big of an issue as it normally could be. 

One thing to be aware of with the heritage 130p is that it comes on a mini Dobsonian base, so you will need something for it to sit on to raise it up to a use able height (e.g. a garden table)

If another user can focus the 6mm eyepiece near the 15mm eyepiece focus position, perhaps there is a fault with your eyepiece. I would try some other eyepieces and see if those focus properly. 

8 hours ago, Da Vinci said:

I could easily do two trips for the OTA and the base, as the location is not that far from car parking. 

 

I have been saving for last 4 months and have saved enough for a 6" f8. Now I can't wait to get my hands on it.  May be after couple of months I could buy some decent EPs as well. If I am going for an 8" f6, I would have to save for couple of months, and I am dying to hold a telescope, sir. 

But I am aslo concerned about the optical performance of 6" f8. Is it good enough for a decent telescope? Is 6" too small an aperture for faint objects?

Well then really it is down to how desperate you are to have a telescope now. If you absolutely have to have a telescope now then the 6" is a good choice and will be a good performer. If you can bear to save for a few more months then the 8" will be just a little bit better on DSOs due to the additional apperture and is worth saving for. Of course the 10" is then a little bit better again than the 8" and the same again for a 12" over the 10". You have to draw the line somewhere and where you draw that line is up to you. 

25 minutes ago, Da Vinci said:

I intend to drive up to a nearby mountain for my weekend observation sessions. Will it be too much to carry an 8" dob? 

When you arrive at the location, how far will you need to carry the telescope from the car? Can it be done safely in more than one trip? (i.e. can you carry the base to the location and then go and get the OTA?) 

If you are only going to observe a short distance from the car so that you can carry the telescope in a couple of trips, or if the ground is flat and even so that you can safely carry in one piece I would definitely go for the 8". If you need to carry the telescope quite far or the ground is uneven and difficult to walk over, a smaller, more transportable telescope is going to be better. 

10 hours ago, AdeKing said:

I've used them with my Maxbrights and it can be a bit of a faff if you are swapping eyepieces every five minutes, but if you're swapping only occasionally then its not too bad.

The material is fairly flexible so easy enough to pull over the end of small eyepieces in the binoviewers. 

Thanks. It sounds like they might be worth a try with binoviewers, although perhaps an observing hood would still be a better bet in that situation. 

Has anyone tried using these with binoviewers? Are they a pain to keep fitting with eyepiece changes? 

8 hours ago, W0nderste said:

Thanks.

dumb question then, but why give the scope a 2" connector if you are better with 1.25 diagonal and 1.25 EPs

The 2" barrel allows someone with a 2" eyepiece clamp to put the eyepiece straight into the 2" clamp without using a reducer, but you do not remove the 1.25" section of the eyepiece to do this. 

The problem with this approach is that the 1.25" section protrudes a long way below the 2" section and you don't want to damage anything by pushing the eyepiece in too far, for instance the mirror in your diagonal, and so it really only serves newtonians with a good amount of out focus travel.