John

Just now, Adam J said:

Is your 4 inch currently in orbit around mars? 

The UAE have borrowed it for their Mars mission

3 hours ago, Deadlake said:

Using the spreadsheet on 30/31mm 2" EP's,  FL = 900 m and F6 gives: 

1 Brand	Model	Type	FL	Diam.	AFOV	Price	Exit Pupil	Eye Relief	Calc.FieldStop
Celestron	Luminos	UltraWideField	31	2.00	82	$ 269.95	5.2	27.0	44.4
TeleVue	Nagler5	UltraWideField	31	2.00	82	$ 666.00	5.2	19.0	44.4
Antares	W70	Wide-Field	31	2.00	72	$ 97.46	5.2	16.0	39.0
Baader Planetarium	Hyperion Aspheric	Wide-Field	31	2.00	72	$ 209.99	5.2	18.0	39.0
Explore Scientific	3" Series	Hyperwide field	30	3.00	100	$ 999.99	5.0	17.0	52.4
Explore Scientific	82 Series	UltraWideField	30	2.00	82	$ 369.99	5.0	21.0	42.9
OpticStar (Opticstar Brand)	XL Ultra Wide Angle	UltraWideField	30	2.00	82	$ 336.25	5.0	21.0	42.9
Astromania	UltraWide 80	UltraWideField	30	2.00	80	$ 90.89	5.0	16.0	41.9
KnightOwl (may not be available)	Ultra-Wide	UltraWideField	30	2.00	80	$ 74.95	5.0	28.0	41.9
Moonfish	Ultra Wide	UltraWideField	30	2.00	80	$ 145.00	5.0	22.0	41.9
Olivon	Superwide ED	UltraWideField	30	2.00	80	$ 147.00	5.0	16.0	41.9
Altair Astro (UK)	UltraFlat	Wide-Field	30	2.00	70	$ 219.70	5.0	22.0	36.7
APM	Ultra Flat Field	Wide-Field	30	2.00	70	$ 229.00	5.0	22.0	36.7
Explore Scientific (Bresser)	70° Series	Wide-Field	30	2.00	70	$ 119.99	5.0	?	36.7
GSO (Guan Sheng Optical)	Superview	Wide-Field	30	2.00	70	$ 64.95	5.0	22.0	36.7
Pentax	SMC-XW	Wide-Field	30	2.00	70	$ 369.95	5.0	20.0	36.7
Telescope Service	UFL	General Use	30	2.00	69	$ 120.32	5.0	16.7	36.1
OVL (First Light Optics)	Aero ED	Wide-Field	30	2.00	68	$ 117.81	5.0	16.7	35.6
Skywatcher	Aero ED	Wide-Field	30	2.00	68	$ 131.25	5.0	16.7	35.6
Telescope Service	Wide Angle	Wide-Field	30	2.00	68	$ 92.34	5.0	?	35.6
TPO (from OPT)	SuperView (Erfle)	Wide-Field	30	2.00	68	$ 64.95	5.0	20.0	35.6
Vixen	NLVW	Wide-Field	30	2.00	65	$ 219.00	5.0	22.4	34.0
Kitakaru	RPL	General Use	30	2.00	62	$ 115.99	5.0	15.0	32.5
Sterling (Smart Astronomy)	Plossl	Plossl	30	2.00	55	$ 79.95	5.0	18.0	28.8

Choice seems to revolve around AFOV and exit pull, given most pupil relief is over 20 mm.

Trawling the CN threads and the 31 mm Nagler seems a default in each EP storage box, why does it @Johnjustify almost double the price of the other premium EP's around 30mm? 

The ones that jump out to me are:

1. Televue Nagler 31
2. Explorer Scientific 82 Series
3. APM UUF 
4. TS UFL

The Pentax and Vixen are good, but are reportedly behind the others.
 

 

I've owned the 31mm Nagler longer than any of my other eyepieces. Explore Scientific were not in the game when I bought it. I'm not very good at justifying the costs of quality equipment I'm afraid

I don't use the Nagler 31mm very much since I got the 21mm Ethos, the cost of which would be even harder to justify with things like the APM 20mm / 100 around now.

I did compare the Nagler 31mm with the Pentax XW 30mm and the Nirvana / UWAN 28mm quite a few years back:

3bigeps.pdf

It is interesting to note that the Pentax XW 30mm is £100 less expensive today than it was back in 2009 when I compared them. The Nagler is £200 MORE expensive now than it was back then.

1 hour ago, Voyager 3 said:

John are your Tak 100 and SW 120 more alike than different ? ( In light gathering and resolving power ) 

The other scope in that picture is my 130mm F/9 TMB/LZOS triplet. 

The SW ED120 is in this picture along with my Vixen ED102SS, the Tak and the TMB/LZOS:

The Tak gets very close to the SW 120 in terms of resolution but the additional 20mm is noticed on really tight binary stars and in light grasp on deep sky objects.

The TMB/LZOS performs very like the Tak in terms of pure image quality but with 30% more aperture. I guess similar to a Tak TOA 130 ?

1 hour ago, Stu said:

I don’t think I would ever be without a 4” scope, if only for the sheer convenience and portability whilst still offering great performance....

 

Yep, me too. 100mm F/9 vs 130mm F/9. 4Kg vs 9.5kg:

To be fair, a 150mm F/8 doublet is about the same size and weight as the 130mm triplet though.

2 hours ago, mikeDnight said:

A friend of mine bought a Meade 127 triplet that I'm pretty sure used FPL51. This was quite some time ago and I hate anything with the Meade label on it. Honestly, that scope was as colour free  (visually) as any apo I've ever used....

I think they might vary a bit Mike. I used one which showed a touch more CA than my ED120 doublet did.

I think this comparison involves a similar scope:

https://astromart.com/reviews-and-articles/reviews/telescopes/refractors/show/orion-120ed-vs-astro-tech-127edt

I find a higher magnification darkens the background sky and helps to tease out the fainter DSO's but I want to maintain a large true field as well. Hence UWA and HWA eyepieces. More £'s as well of course

20 minutes ago, Deadlake said:

Maybe I should try the 30 mm first, is the APM based on the paragon design?

http://apm-telescopes-englisch.shopgate.com/item/333631373637
 

That is an eyepiece of a different design. It gets good reviews so a worthy contender if 30mm will suffice.

3 minutes ago, 7170 said:

Given the endless cloudy nights we’ve had here in the UK since September I’m surprised demand for astro gear from people taking up the hobby is high at all!

I suspect once things get back to normal many people who dabbled in astronomy over lockdown for the first time will return to previous interests that can be pursued once again.

When it all hits the used market, at least it will be "low mileage"

Until recently I had a 40mm Aero ED. These were originally available in the USA under the Astro Tech branding as their Titan II range and I believe had the same optics in them as the TMB Paragons. The Paragon range was 40mm and 30mm. The Aero ED's included a 35mm as well. I had the 30mm and the 40mm. The 30mm was quite good but the 40mm was excellent. Very well corrected at the edge of field for it's price in my F/6.5 Vixen ED 102 refractor and even in my F/5.3 12 inch dobsonian although the exit pupil was not terribly effective in that latter scope.

The Aero ED's (also available under other brandings) are also reasonably light for 2 inch eyepieces.

Unfortunately I can't see the 40mm listed anywhere now but if you do come across one they are worthy of serious consideration for use in F/6 and slower scopes.

I let mine go for a silly price a couple of months back simply because I find shorter focal length UWA's and Hyper-Wides more effective under my moderately light polluted skies. Probably should have hung onto it

Going a bit too far perhaps ?

The scope is 67mm Borg. The eyepiece and diagonal are 3 inch format:

The Helios is the same instrument as the Skywatcher Evostar 120mm. The manufacturer (Synta) used the brand name Helios before moving to Skywatcher.  I think the Soligor refractor is made by GSO, Guan Sheng Optical in Taiwan.

6 minutes ago, Goldenmole said:

Yeah this is the thing, isn't it, that you can probably see colour through a large aperture, but not from a refractor. By the by, where is the snowball nebula located, pray? I'm new.

The Blue Snowball (NGC 7662) is in Andromeda. It's not all that far from Messier 31, the Andromeda Galaxy:

I've seen a greenish tinge around the "fishes mouth" part of the nebula fairly often with my 12 inch dob. Very occasionally, when I've used a UHC filter I felt that I might have detected traces of a pink tinge as well but that might be the effect of the filter.

51 minutes ago, Soligor Rob said:

Thanks for that, I wasn't certain if a daylight test was the best option

Can you explain why Their  focal Ratios are not particularly demanding on eyepieces?

Would I be better quality Diagonal if there is such a thing help? or buying the X-Cel Barlow.

Thanks.

The focal ratios of these long refractors are F/10.75 for the 93mm (although I think that might really be a 90mm) and F/8.3 for the 120mm. These are considered relatively "slow" focal ratios by todays standards so the light cone they produce is not as steep as a "faster" scope would produce and this means that the optics within the eyepiece do not have to be too sophisticated / complex to deal with it effectively, ie: without adding optical issues.

Better quality accessories such as diagonals, barlows and eyepieces can improve things a bit but won't turn a poor scope into a good one.

Having used both the types of scope that you have, they are not poor scopes anyway. They actually perform pretty well.

You said in the earlier post that you learned a lesson that these scopes aren't that good - was that though your own experience of using them or from what you have read ?

Why not try them at night on astro targets and see how they perform then ?

Both these refractors are good performers. Their focal ratios (focal length divided by the diameter of the objective lens) are not particularly demanding on eyepieces so you probably won't see much difference between using the 25mm plossl and the more expensive Celestron X-Cel LX 18mm, apart from the latter giving a bit more magnification.

As has been said - get them out under the stars and they should both deliver some very satisfying views.

BBC report and images returned from the latest ESA mission to the red planet:

https://www.bbc.co.uk/news/science-environment-55943374

NASA's latest martian rover is scheduled to arrive there in less than a week:

https://mars.nasa.gov/mars2020/

It might be getting smaller in the eyepiece of our scopes but still lots to get excited about on Mars

20 minutes ago, KP82 said:

Yep. Doublets are easier to make than triplets plus 100mm is considerably smaller than 130mm, so I wouldn't be surprised to see a good sample of 100DZ beating a poor sample of TMB 130 f/9.2.

I think Takahashi maintain very consistent standards. I've not heard of any poor LZOS objectives. I think APM has quite stringent minimum specs for LZOS to meet:

https://www.apm-telescopes.de/media/files_public/uguxbbhkgbx/APMApo-Linsen-Spezifikationen.pdf

There will of course be the odd one that slips through the net.

I guess it is the level of quality control and consistency that one pays for with these premium priced items.

These threads should explain a bit about what is happening:

https://stargazerslounge.com/topic/371781-sky-watcher-price-increases/

https://stargazerslounge.com/topic/363878-astronomy-sales-during-the-pandemic- update/

2 minutes ago, KP82 said:

According to those 4 graphs, the theoretical performance are: 130 f/9.2 > 100DZ > 100DL > 125ED

That's a good point - these are theoretical charts for the lens design. Individual units might vary I guess ?

I've been interested in getting to the bottom of such diagrams for some time so I will follow this thread with interest

This is the one for the LZOS 130 F/9 triplet:

I think that the number of "crossings" and where they occur is part of the performance picture but how that all adds up I'm rather in the dark about

35 minutes ago, Nik271 said:

I had a similar experience as @Waddensky last night with 180 SW Mak:  The disc size of Sirius was well controlled most of the time and a couple of times I thought I saw a fleeting pinpoint north-east but it did not reoccur regularly enough to be sure.

I believe 250-300x is the right magnification to use in my scope: Sirius B is almost 9-th magnitude and being low in the sky atmospheric extinction will make it even dimmer. And magnification larger than 300 will make it just too dim. Magnification 250x should make 11'' separation appear as 44' in the eyepiece, so hopefully wide enough to separate from the glare. I'm still waiting for the perfect night to see the Pup🤞

 

I managed to see the Pup star with my 12 inch scope at 199x, 265x and 338x a couple of nights back so your range is about right I think. 265x (6mm eyepiece with my dob) does the best job.

Last night I did have a try with my ED120 refractor but the seeing here was unsteady - even somewhat easier pairs were tricky

11 hours ago, johninderby said:

Bit more info. Also supposed to be the same optics as in the WO Zenithstar 126

I'd love to be able to understand these charts !

This is the one for the LZOS 130 F/9 triplet for comparison:

The 125 ED doublet scope does look really tempting though

I recall when the Altair 125 ED doublet came out it caused quite a stir. The Tecnosky is less expensive though but I wonder if otherwise they are the same scope ?

I've spoken with Rupert as Astrograph on a couple of things (he used to stock the T-Rex mount and still carries the LZOS / APM refractors) and he seems a really helpful and knowledgeable chap.

If you get one, I will really look forward to reading your views on it

2 hours ago, scarp15 said:

Congrats on the TV O-III, as Gerry had mentioned, Ursa Major is gaining prominence and M97 will 'pop' with the addition of the O-III filter in the optical light path.

It sure will

Also worth trying to find without a filter so that the nearby galaxy, Messier 108, can be seen in the same, low power, field of view. I love these "2 for the price of 1" observing opportunities

http://www.ianmorison.com/rich-field-telescopes-and-wide-field-observing/

7 hours ago, malc-c said:

What an open ended question... How the hell can we tell you what your options are..... We have no idea of your budget, your interests or what you intend to do (visual or imaging!).

Both mounts you list are decent, and each have pros and cons, but none of us can advise which would suit a particular use or need as you've failed to mention what those are...

Come back with some more detailed information and then other members can voice their opinions

What happened to the concept that "there is never a silly question on this forum" ?

If some more info would be helpful to make suggestions, why not ask some questions ?

Maybe the OP is not sure what information to offer up to get some suggestions of upgrade options ?