Louis D

When one of my illuminators died due to bad solder joints that I gave up resoldering; I just bought a cheap, used 12mm Meade Astrometric MA with working illuminator simply for the illuminator for $35 a couple of years back.  The eyepiece is terrible, but the illuminator is terrific.

1 hour ago, Orange Smartie said:

 I don't think they have stock though, a story you may find repeated at every telescope website.

Yes, I think 2nd (or even 3rd or 4th) hand equipment may be the OP's best bet to get something decent at an affordable price now.

I've even known astro sellers to throw in some basic eyepieces they have lying around unused with scopes that didn't come with any once they find out the purchaser is a newbie and has none.

3 hours ago, badhex said:

1x barlow (currenlty own a 2.5x Revelation/GSO)

Also be aware that this Barlow has been reported to be closer to 2.2x.

Well, no, I've never had the need to replace an illuminator pot.  All I can suggest is to run it back and forth a bunch to redistribute the conductor and/or scrape off the internal oxide build-up within the pot.  This works great with audio equipment pots when they get "noisy".

I tend to use binoviewers only for solar system objects.  I have a dedicated 1.25" diagonal for them to reduce focuser in-travel.  I rarely swap between binoviewing and monoviewing during a single observing session.  It's not that big of a deal on a Dob, but it is a bit more of a pain with refractors and CATs since it requires swapping diagonals.

35 minutes ago, badhex said:

For the low power, I appreciate the FOV will be  restricted by the 1.25" barrel size at low powers, but is it worth adding at least half a kilo for the diagonal plus whatever EP, for that extra degree of sky? 3.8° TFOV vs 4.8.

Not sure where you're getting 4.8 degrees for a max field 2" eyepiece.  Let's assume a 70 degree AFOV 40mm 2" eyepiece such as the 40mm Pentax XW.  It would yield roughly 420/40 = 10.5x with a 70/10.5 = 6.67 degree TFOV.  That's a huge difference relative to the 3.8 degree TFOV of the 32mm Plossl.  Nearly 3 degrees wider.  I do this a lot with my AT72ED when panning rich star fields.  It allows me to pick out clusters and asterisms that are otherwise too big to recognize as such.

For high power, you might try @John's goto of a 7.2-21.5mm zoom combined with a Baader Q-Turret 2.25x Barlow.

Those star shower laser shows may be using as much as 100mW lasers and have been causing issues here in the US.  Are they even sold in the UK given that laser pointer law?

1 hour ago, Zermelo said:

Louis, that may be the case in the US, but over here it is a strict liability offence, i.e. the authorities have only to identify the perpetrator, not to prove malicious intent.

So the mere act of owning or taking delivery of a >1mW laser is an offense under this statute?  The mere act of pointing a laser to the sky is an immediate offense?  How many people were arrested for having those Christmas laser light shows missing the side of the house and pointing into the sky?  I read of a lady in New Jersey who was issued a warning when hers got knocked over backward and was lasing nearby planes.

I did this years ago with a much slower telephoto lens for the OM mount.  I put a short macro extension tube on the rear and added PVC plumbing parts and thumbscrews to hold an eyepiece at prime focus.  It worked well enough that I bought a telescope the next year.  I suppose a T-mount would be better because then you'd have a threaded mount to attach to, but I was unaware of them back then.

1 hour ago, AlexK said:

You haven't explained what you plan to use it for and why. :)))) 

So I assume as some arbitrary visual telescope pointing aid, because you have a sore neck preventing you from using an RDF, Telrad, or an optical finder (a typical reason stated :)))).

At a real dark site (which you have mentioned), I would recommend skipping "gun" laser sights with the bright green beam (which Louis has recommended above). They will blind you just from looking at the beam in the sky at night enough to drop your telescope an inch or two in aperture when observing DSOs. Get a red or blue (violet) pointer instead. Also keep in mind that you can ruin the work of any astrophotographers near you with it.

In my suburban skies, I can't even make out my red and violet laser pointers' beams in the sky.  They're just too dim.

I just use green laser sights purchased from China via ebay.  They're mounted on Picatinny rails or barrel mounts.  They come with momentary switches on a coiled cord making them really easy to use and not forget to turn off.

Unless you make a deliberate effort to lase aircraft, you should be fine legally.  It's people lasing police helicopters and landing planes that ruin their use for everyone else.  I just listen for aircraft and do a quick check of the skies before lighting up to stay out of trouble.

Those mounts are wobbly and difficult to track with at high powers.  It has a three inch spherical mirror of fairly long f-ratio, so it is serviceable optically.  It will provide decent views of the moon and star clusters.

Remember that when buying new, you have to deal with missing parts, stripped threads during manufacturing, and possibly damaged returns sold as new.  With used bought from someone who has been using it, those issues have all been resolved.  It's easy enough for the seller to walk you through the use of the scope if picking up in person.  The seller can demonstrate that motions and image are in good working condition to you.

Generally, the Sky-Watcher Heritage 130 gets the nod for best beginner scope.  It does exceed your budget by a little bit, though.

On 17/04/2021 at 17:17, TRACEY 1409 said:

Hi, I am a complete beginner and an independent site has recommended the celestron starsense explorer 114lt telescope. I have watched videos of this and it looks really easy to set up and I like the fact you can use an app to pinpoint stars and planets that you want to view but how good is this really. I have up to £200 to spend but have seen sites that say a good set of astro binoculars are just as good if not better for a beginner due to the increased field of vision? 

What sort of reputable site would ever recommend a Jones-Bird type telescope?  I'm really curious because they are generally an abomination optically.

It should be the same internally as the original 30mm ES-82 mushroom top that I have along with the 30mm Meade 5000 UWA.  It's a good eyepiece other than the ring of fire effect.  Put the moon out there in the last 15% of the field and watch it turn orange.

It is possible to decloak it to drop a good chunk of its weight and bulk, though I'm not sure of the details how.  My 30mm ES-82 required prying off the upper rubber ring.  It was glued down pretty solidly.

3 hours ago, SilverSurfer said:

Sky Safari 6 Plus has dropped to £9.99 on the iOS App Store (I think from £14.99) and I've just bought it.

Sky Safari 6 Pro has dropped to £25.99 from (I think from £38.99).

Not sure if the Android versions have also been reduced.

Is Sky Safari more accurate the SkEye for use as a DSC app?

The Telrad would be fine for your 10" Dob, but would be a bit of a tight fit on your Z130.  The Rigel works well on smaller scopes, and it has a built in pulsing circuit to boot.

If you're simply having difficulty locating objects, why not just install DSCs?  I found this thread discussing DSC retrofit options for Dobs on CN.  Read it over, and see if there are some good suggestions in there that might apply to your situation.

3 hours ago, johninderby said:

Read a review comparing the earlier TS 90 FPL53 triplet and the new FPL55 TS CF triplet and they concluded that they were equivalent but did say they were excellent optically though.  

Owning the TS 90 FPL53 triplet myself, I'd be interested in reading that review.  Do you have a link to it that you could share here?  My only complaint is acclimation time for the triplet.

3 hours ago, ollypenrice said:

My regular test is a mobile phone mast about 150 metres away

Interesting.  In the US, we refer to them as cell towers.

Congrats on the win and new spotting scope.

5 hours ago, Ags said:

The reason I think in terms of very fast scopes is because I don't want to invest in 2 inch eyepieces - I can do without the expense and I know I dislike heavy eyepieces.

Seems like a huge waste to use 1.25" eyepieces in a 3" focuser.  All that extra weight and bulk for nothing.

10 hours ago, Ags said:

Firstly, NPL has very strong pincushion distortion, more than any other eyepiece I have owned.

If that level of pincushion distortion bothers you, stay away from the 27mm Panoptic and 28mm RKE as they have even stronger pincushion than Plossls (like the NPL).  Notice the bowing of the ruler/yardstick in the last four eyepiece AFOV images below:

11 hours ago, Stu said:

I think the Genesis came first Chris, they were produced between 1988 and 1993 I think. There is a nice history here:

http://www.company7.com/televue/telal.html

The Nag 31mm came along in 1999 apparently.

http://www.company7.com/televue/index.html

 

Here's Tele Vue's own history table documenting the introduction (but not discontinuation) of each product.

14 hours ago, Stu said:

Which scope is that in Louis? As I understand it, scopes and eyepieces have curvature, so the best results are where these cancel each other out. If they reinforce then results can be bad.

The Genesis is a Petzval, and well known for a flat field, so I assume the 31mm Nag has a flat field too. There is some discussion elsewhere about the longer focal length Pentax XWs. I’ve seen a number of reports of field curvature in them, but do wonder if that is because they are designed to counter FC in shorter focal length spotting scopes, so are less good in longer focal length scopes?

That's in my AT72ED with TSFLAT2 and 8" Dob with GSO CC.  The 30mm APM UFF is also dead flat as well in both.

By way of comparison, the 30mm Wide-Field III clone has loads of field curvature in either.  I once moved it well back from the diagonal in the AT72ED with a 2" extension and racked in my focuser to overcompensate the field flattening, and then the 30mm WFIII had a pretty flat field and just residual astigmatism at the edge.  It's a shame it doesn't have a built in field flattening element at the bottom because it would actually make a pretty decent 80 degree eyepiece.  I was able to achieve similar results for my 14mm Pentax XL with about an extra inch of spacing.

9 hours ago, amaury said:

@Louis D, Do you think the same can be achieved with an ES82 24mm? the specs say it has 17.5mm of eye relief, in practice Don mentioned it has more like 14mm of effective eye relief. Haven't read any comments about folding the eyecups in the ES82 eyepieces. 

Since the current generation of ES-82s all have recessed eye lenses, I can understand where it would lose about 3mm of eye relief right there.

I know I can just take in the whole field of my first-gen mushroom top 30mm ES-82 with eyeglasses on.  I've measured it to have 16mm of usable eye relief while the ES spec says 22mm, and that's about how it feels, or possibly 17mm.  You have to press in to take in the entire field of view, but it is doable without scratching your glasses.

Since the 24mm version has a smaller eye lens, I would expect less usable eye relief in the original gen-1 version, and even less with the current gen's recessed eye lens.  I'd guess probably 13mm of usable eye relief, which is great if you're not wearing glasses.