Eyepiece advice

[DPF]

After having so much great advice with my first post and managing to have the occasional clear skies, I’m back for more.

With my beginners Travelscope 70, I’d like to get closer views of planets and if possible nebulae.

With a significant birthday coming up, I’m being asked for ideas and would like to take the opportunity to get some new kit.

What eyepieces and magnifications would you recommend?

 

[RT65CB-SWL]

Hi @DPF

For my TeleVue Ranger, the smallest fixed length e/p I use with it is 6mm... and even 3mm with the TeleVue Nagler 3-6mm zoom. 

If you are on a tight budget, then these are highly recommended by some... https://www.firstlightoptics.com/bst-starguider-eyepieces.html
or you could try these... https://www.firstlightoptics.com/vixen-eyepieces/vixen-npl-eyepieces.html

For DSO stuff you could try a Baader Neodymium or a UHC. I use both, though I find the Neodymium is the most used and universal
of my filters. I often refer to it as my 'Swiss-army knife' filter.

 

 

Edited February 7, 2021 by Philip R

[Second Time Around]

Hi and welcome.

What's the budget likely to be?

[Tiny Clanger]

The spec of your scope ( according to Celestron) is

	Aperture: 70mm  Focal Length: 400mm Focal Ratio: f/5.7 , and it comes with 20mm and 10mm eps The generally accepted rule of thumb is to not exceed a magnification greater than double your 'scope aperture in mm, so max of 140x , but a more comfortable and usable mag. will be less than this , maybe 1x or 1.5x the aperture  , say 100x To find the mag. with an eyepiece in your 'scope take the 'scope focal length (400mm in this instance) and divide it by the ep designation , so your 10mm ep gives you 40x, and in theory you could go to  a  4mm ep to give you 100x I suspect pushing the travelscope further than this will just result in showing up the wobble in the tripod and mount and be disappointing. The budget (ie. around £45 each) eyepieces everyone recommends here are the BST starguiders, and they are good, I have a few, the 8mm is very nice indeed, but they are quite heavy for a small light 'scope and mount .There is a 5mm BST, but I have not used one myself so will leave it to someone who has to comment on it. I've never used a zoom eyepiece either, but I'm sure someone will be along to recommend some soon . Other good items to add to the birthday wish list are a copy of the excellent 'Turn Left at Orion' for £25 ish , or a barlow to double the mag, of any eyepiece you have ( prices from £25 ish to how much !!! https://www.firstlightoptics.com/barlows.html Heather

[Mr Spock]

Some good advice already. The BSTs are good for you scope and a 3.2mm BST will push it to the limit (they don't make a 4mm) at x125.

Another suggestion would be to get a low power eyepiece. A 32mm Plössl will give x12.5 and a 4° field of view.  You'll get some fascinating wide field views with that.

[DPF]

Hi all and thank you once again for your advice - this forum is so helpful and supportive.

I'm going to get a more sturdy tripod for the telescope, as the wobble does cause problems and at the moment I’ve been using the tripod on a shorter height to gain more stability, whilst raised on a solid surface. 

I did buy ‘Turn Left at Orion’ and have been working my way through that, albeit slowly.

A Barlow lens is also on my birthday wish list, along with a 90 degree diagonal, as the Travelscope I have came with a 45 degree.

Also asked for a 5mm BST eyepiece.

Hopefully, this may all make a difference and at some stage I’ll take the plunge for a stronger telescope.

 

[Tiny Clanger]

18 hours ago, DPF said:

Hi all and thank you once again for your advice - this forum is so helpful and supportive.

I'm going to get a more sturdy tripod for the telescope, as the wobble does cause problems and at the moment I’ve been using the tripod on a shorter height to gain more stability, whilst raised on a solid surface. 

I did buy ‘Turn Left at Orion’ and have been working my way through that, albeit slowly.

A Barlow lens is also on my birthday wish list, along with a 90 degree diagonal, as the Travelscope I have came with a 45 degree.

Also asked for a 5mm BST eyepiece.

Hopefully, this may all make a difference and at some stage I’ll take the plunge for a stronger telescope.

 

Ah, I wondered about suggesting a star diagonal, but wasn't sure if you were happy with the original. I bought the one which comes in at around £70 new ( FLO do 2, one is skywatcher one other brand, they are identical in every respect ) I bought one second hand to upgrade the stock one on my little mak and it is much better made, holds the ep firmly and doesn't feel flimsy or unscrew itself from the 'scope !

I'd consider changing your request to an 8mm bst if you are getting a barlow as well , the 8mm will probably be better most of the time, and with a 2x barlow will give you 4mm.

If you get the 5mm BST and barlow it, you will get 2.5mm which I suspect will probably be too great a magnification under most skies for your 'scope.

Heather

[wibblefish]

I recently acquired my telescope (90mm refractor) and after looking at various threads in this forum I upgraded the 25mm / 10mm eyepieces to a set of BST 25 / 18 / 12 and a barlow with the idea the 12mm would be a 6mm and plenty of magnification. What I found was the weight of the barlow + eyepiece gave some hairy moments with the balance of the telescope plus I had trouble gaining focus if I then tried to use an additional filter with that combo as well as plenty of high mag focusing shake due to the tripod. It might just be the one I had but its something to bear in mind with lighter weight telescopes when you buy decent but much heavier eye peices.

With a bit of weight to combat the shake (I bought some wrist weights and wrapped them round the tripod legs) and purchasing an 8mm I found it was much less weighty than the barlow + 12mm combo. If I really want to the 8mm + barlow (so 4mm) would give me a 165x magnification which is probably approaching the high end of useful magnification for the telescope.

Another suggestion might be to look into a zoom eyepiece but I have no experience with them unfortunately but plenty on here will have I am sure.

Edited February 8, 2021 by wibblefish

[Tiny Clanger]

38 minutes ago, wibblefish said:

I recently acquired my telescope (90mm refractor) and after looking at various threads in this forum I upgraded the 25mm / 10mm eyepieces to a set of BST 25 / 18 / 12 and a barlow with the idea the 12mm would be a 6mm and plenty of magnification. What I found was the weight of the barlow + eyepiece gave some hairy moments with the balance of the telescope plus I had trouble gaining focus if I then tried to use an additional filter with that combo as well as plenty of high mag focusing shake due to the tripod. It might just be the one I had but its something to bear in mind with lighter weight telescopes when you buy decent but much heavier eye peices.

With a bit of weight to combat the shake (I bought some wrist weights and wrapped them round the tripod legs) and purchasing an 8mm I found it was much less weighty than the barlow + 12mm combo. If I really want to the 8mm + barlow (so 4mm) would give me a 165x magnification which is probably approaching the high end of useful magnification for the telescope.

Another suggestion might be to look into a zoom eyepiece but I have no experience with them unfortunately but plenty on here will have I am sure.

Yep , I suspected wobbles (or possibly wibbles 🙂 ) might be a problem .

It's easy to be sucked into the 'bigger the mag, the better' thing, without thinking of the trade offs : wobbles are magnified just as much as the view is, any judders from the mount when moving the 'scope are magnified ditto. Then the increased mag comes with decreased field of view, so if you are looking at something relatively fast moving (The Moon or Mars for instance) it zips across the ep field of view in moments. And it is harder to aim the 'scope accurately , so best start with the stock 25mm and centre your target, then swap EPs and hope the thing's not moved, or you didn't accidentally nudge the 'scope when swapping ...

A lot of 'catalogue' and amaz. consumer 'scope adverts emphasize mag. so much that they are almost certain to be a disappointment in use .

When Mars was at its closest to us in the summer I found it just too speedy to leave my view for 2x barlowed 8mm bst in my heritage 150 , which has a focal length of 750mm, so that's a mag of x187 . I could see the surface markings far better by using the 8mm alone (94x) simply because the planet was there to concentrate on for longer before I needed to nudge the 'scope along. 

Might be worth mentioning that the better diagonal is a bit heavier than the standard SW 1.25" stock one which came with my 127 mak too, so if the extra weight of EPs is likely to be a problem with balancing your 'scope, the upgraded diagonal will add to it. No worries for my little mak, as I have it on a mount tripod combo which could in theory carry it 3 times over and is very stable.  I'm a fan of investing in a good mount and tripod, less glamorous than the 'scope on top, but vital for easy and effective viewing.

With the dob, which has a steel tube, I use a magnet salvaged from a dead hi fi speaker and used it to quickly rebalance the tube when swapping between BSTs and the lighter weight plossls which I still use : the 32mm skywatcher plossl (£30 ish) gives a very similar FOV to the 25mm BST and I sometimes prefer it in the relatively fast dob, while the BST is superior in the slower mak .

Heather

[wibblefish]

@Tiny Clanger I think I am maybe using the wrong word, the telescope isn't out of balance (i.e. would pull the tripod over) its just I have had moments where the clutch has "slipped" off target when the additional weight was first applied if that's a better way of putting it? 

My main reason for high magnification is for trying to split double stars but there is going to be a limit to how useable it will be, I think the often quoted figure is 180x in UK skies but in practice it may be lower). I have pushed my refractor to the limit trying to see various things in recent nights (faint DSO, tight doubles etc.) and whilst that is great fun (if frustrating at times) it is much more suited to seeing those big wide field views at the low magnification end and getting lost amongst the star clusters

Edited February 8, 2021 by wibblefish

[Tiny Clanger]

I was taking balance as having the clutch entirely loose , and letting the 'scope tube find its own level, then sliding the vixen/SW/whatever bar/rail/whatever back & forth until the 'scope (with an ep in , of the most used type) is dead level.

The heritage dob alt bearing is just a large knob you tighten, no gears or anything, so it needs the 'scope to be well balanced to move easily , or else when you undo it the tube swings vertically . The knob has a pretty strong action though, so it locks solidly, and as long as it is released gradually it's not hard to find a good point between solidity and ease of movement. I suppose that's the result of the simple hefty dob base design.

Yep, wide view, lower mag, big stuff, a 'scope is good for ... what it's good for ! That's why I supplemented the little dob with a mak for the small bright stuff 🙂  I'd genuinely suggest someone wanting to spend under £400 and 'see everything' (as the request usually says) ought to consider 2 scopes, a wide field one (short refractor or 130 newt. on an alt az , or a heritage dob, whatever they fancy) and a 102 mak . for the narrow field views.

Heather

 

[wibblefish]

15 minutes ago, Tiny Clanger said:

I was taking balance as having the clutch entirely loose , and letting the 'scope tube find its own level, then sliding the vixen/SW/whatever bar/rail/whatever back & forth until the 'scope (with an ep in , of the most used type) is dead level.

The heritage dob alt bearing is just a large knob you tighten, no gears or anything, so it needs the 'scope to be well balanced to move easily , or else when you undo it the tube swings vertically . The knob has a pretty strong action though, so it locks solidly, and as long as it is released gradually it's not hard to find a good point between solidity and ease of movement. I suppose that's the result of the simple hefty dob base design.

Yep, wide view, lower mag, big stuff, a 'scope is good for ... what it's good for ! That's why I supplemented the little dob with a mak for the small bright stuff 🙂  I'd genuinely suggest someone wanting to spend under £400 and 'see everything' (as the request usually says) ought to consider 2 scopes, a wide field one (short refractor or 130 newt. on an alt az , or a heritage dob, whatever they fancy) and a 102 mak . for the narrow field views.

Heather

 

Ah yeah I don't know anything about Dobs Mine is balanced enough that it wont do much even with the clutch off until it is tipped back quite far (as one would expect) the only exception seems to be sometimes I have had the tube slip even on full clutch when inserting EP (usually the weighty EP + barlow combo - so much heavy glass!) so it was just a thought  

I am getting a new diagonal tomorrow so will see how the extra weight affects it, likely I will be pushing the dovetail as far forward as possible as there is no weight on the front of the tube and the pronto is a top load mount. I could probably do with bolting an extra weight or something on the dovetail if that is even a thing that exists or perhaps I should just wrap the spare 1kg wrist weight I have over the front of the tube to give it a bit more weight on that side of the mount head (wether that will make the payload to heavy is a completely different question though!) 

Yeah concur on the telescopes, I am only a few months in but I know I am going to need another telescope to see all the things! I do wonder about upgrading to the next size of short tube (127S) just for more light grasp and giving this one away. I suspect the right answer is to complement with an 8" Dob or a 127 Skymax or some such but I'll wait a while before posing that question to the group

 

Edited February 8, 2021 by wibblefish

[Tiny Clanger]

5 minutes ago, wibblefish said:

Ah yeah I don't know anything about Dobs Mine is balanced enough that it wont do much even with the clutch off until it is tipped back quite far (as one would expect) the only exception seems to be sometimes I have had the tube slip even on full clutch when inserting EP (usually the weighty EP + barlow combo - so much heavy glass!) so it was just a thought  

I am getting a new diagonal tomorrow so will see how the extra weight affects it, likely I will be pushing the dovetail as far forward as possible as there is no weight on the front of the tube and the pronto is a top load mount. I could probably do with bolting an extra weight or something on the dovetail if that is even a thing that exists or perhaps I should just wrap the spare 1kg wrist weight I have over the front of the tube to give it a bit more weight on that side of the mount head. 

Yeah concur on the telescopes, I am only a few months in but I know I am going to need another telescope to see all the things! I do wonder about upgrading to the next size of short tube (127S) just for more light grasp and giving this one away. I suspect the right answer is to complement with an 8" Dob or a 127 Skymax or some such but I'll wait a while before posing that question to the group

 

The heritage dob needs careful balancing, 'cos the front end is mostly air  🙂  , so the rear of the scope (mirror and solid tube bit) is far heavier than the front. As it is quite long when opened out balance is critical for ease of use.

The pronto mount I assume has a similar setup to the az5, so you loosen the clutch to move the 'scope, tighten it, then use the slo mo controls to fine tune and follow? I'm entirely ignorant on the inner workings of these mounts, but wonder if there are screws which can be tightened to adjust how closely the gears mesh ? If so maybe you can adjust things to work a little better without torturing the poor thing with ankle weights  🙂

Most of my worries about the mount under the 'scope being wobbly and pushed a bit far by the diagonal & BSTs were really aimed at the OP , altho' I didn't make that properly clear when I replied to your post . Their travelscope comes on a tripod you can see here :

https://www.amazon.co.uk/Celestron-21035-Travel-Scope-Telescope/dp/B001TI9Y2M

Heather

[MrFreeze]

The travelscope I think is dwarfed by the BST eyepieces, and will be seriously unbalanced. I have one of these and it gives very pleasing views of the moon. The Celestron OMNI plossl eyepieces are good, light enough for your scope, and quite cheap if bought from Aliexpress. The shorter focal lengths do suffer from poor eye relief and fairly narrow FOV however. For a wider FOV eyepiece with better eye relief you could try these 70 degree SWA ones https://www.ebay.co.uk/itm/Multicoated-1-25-Eyepiece-8mm-70-SWA-High-Achromatic-for-Astro-Telescope/324447037917. They are much lighter than the BSTs, and I find them to be decent quality. (I have the full set)

I have a Zomei Q100 mini tripod for my Travelscope - it will even fit in the same bag/rucksack and is much less wobbly.

David