John

Great report Rob !

Nice, contrasting, pair of scopes to observe with

9 minutes ago, paulastro said:

Have a good session John. 🙂

Thanks !

Having had a little read of my copy of "21st Century Atlas of the Moon" I'd like to try and see the volcanic dome Kies Pi which should be showing quite nicely. If I'm lucky I might be able to see the 2km crater on it's summit

Loads of other stuff in the Mare Humorum area as well !

The forecast is clear until around 9:00 pm here tonight so I might get an hour or so in.

Thanks for the heads up on Gassendi and Schiller

3 minutes ago, Don Pensack said:

They're the wrong shape.  The phone adapters all require more cylindrical eyepieces.

I wonder if the exteriors of the eyepieces could be removed?

You can unscrew the rubber top section of the BST Starguiders which leaves a more suitable shape for mounting the phone adapter:

ST80 = "Every home should have one"

1 hour ago, Carl Au said:

..... It's getting like astro top trumps in here, it never used to be like this in SGL. 

 

 

You make a very valid point there Carl.

We really should spend more time discussing how folks can get the best out of what they already have rather than fuelling a continual "race to the top".

6 hours ago, mikeDnight said:

The 7mm Nagler was one of my favourites, although my prefered version was the 7mm smoothy.  I made all my observations of Mars in 2003 using my FS128 and a 7mm Nagler, so I have fond memories of it. ☺

My first Naglers were the 7mm and 4.8mm "smoothsides". Very sharp eyepieces

I've owned both these eyepieces in the past 18 months but I can't recall much about them. I guess they were OK for £30 eyepieces (both bought used) but nothing special.

I recall that the edge correction of the BST Starguider 25mm was not as good as I'd hoped it might be. The 27mm EF was nicely made but still a bit ragged at the edge, view-wise. The usable eye relief was about the same I think but I don't wear glasses to observe.

I didn't own them at the same time though so I didn't get a chance to compare them "back to back" as it were.

A decent 25mm plossl (eg: GSO) is probably as good.

24 minutes ago, John said:

Some folks who observe in the US desert with very big dobs have posted some very interesting comparisons on eyepiece effectiveness over the years. Their findings seem to be that for small and faint galaxies, quality orthos are the very best (Zeiss ZAO in their case) followed (quite closely) by the 10mm Baader Classic Ortho and then the 10mm Delos and Ethos. They rate all these eyepieces but when the chips are down, they could see some performance differences on very challenging targets. They had similar results in the 6mm focal length.

Here is their website. It's well worth exploring:

http://www.faintfuzzies.com/

 

 

Thinking it though though, these folks using 30 inch dobs are up ladders when observing. You can comfortably carry a few orthos in your pockets to save coming back down the ladder again. Try that with Ethos's and your trousers will fall down because of the weight. Not what you want in the dark, in the desert, up a ladder

Not a factor that is generally covered by comparison testing

11 minutes ago, Highburymark said:

My SW Equinox 80ED was a great scope - but was not a full apochromat. On tough targets, it would show some false colour. But it was F/6.25. In comparison, F/7 TV85 clears up almost all false colour and F/7.4 Tak FC100 is colour free in focus. 

I guess you need a decent triplet to get rid of false colour more or less completely at F/6.3 ?

7 minutes ago, Stardaze said:

They’re probably a fair way off. I’d be happy with 13/8/6 and the XW 5/3.5 I think. That’s the plan, but having a leaner year this year..

Keep contemplating a grab and go frac option but might just get some Apollo 15x30’s for now too. Too many ‘wants’

I had them both at one point. I recently re-bought the Ethos SX 4.7 because I missed having it to use with my 12 inch dob.

The XW's are the choice for my refractors though.

2 hours ago, Littleguy80 said:

With my 10” F4.7 dob, I’ve been going through my own debates on these focal lengths over the past few months. Originally I had a 13mm and 9mm APM HDC. 100 degree eyepieces felt like the way to go. What I could never escape from was that my orthos gave better contrast and sharpness than the APM’s. In the end, I settled on sacrificing FOV for image quality. The 9mm APM was replaced with a 10mm Delos. When observing, I found that I was regularly skipping the 13mm and going straight to the 9mm. As Piero said, the 2mm exit pupil is the place to be for DSO’s. In the last couple of weeks, I’ve replaced the APM 13mm with a Docter 12.5mm which also Barlows nicely with the Baader VIP to fill the gap between the 10mm Delos and 5mm Pentax XW. 

In terms of real world performance, my 9mm Ortho (BGO) shows 4 cores in Stephan’s quintet. The 10mm Delos is a shade behind the Ortho but will still show the same 4 cores. I was never able to see the Quintet with the APM. 100 degree eyepieces are great, my 20mm APM is a keeper, but they are a compromise. I’ve not tried an Ethos but suspect that even they sit behind the Delos. To make your decision it’s really a question of what you value most and what you’re prepared to sacrifice in your observing...and bank balance  

Some folks who observe in the US desert with very big dobs have posted some very interesting comparisons on eyepiece effectiveness over the years. Their findings seem to be that for small and faint galaxies, quality orthos are the very best (Zeiss ZAO in their case) followed (quite closely) by the 10mm Baader Classic Ortho and then the 10mm Delos and Ethos. They rate all these eyepieces but when the chips are down, they could see some performance differences on very challenging targets. They had similar results in the 6mm focal length.

Here is their website. It's well worth exploring:

http://www.faintfuzzies.com/

A lot of the F/5 achromats that I've used (and a few of the F/8 and slower ones as well) have shown spherical aberration (SA) as well as the expected amounts of chromatic aberration (CA). In my view, SA does more to scrub off contrast and sharpness, especially at higher magnifications, than CA does.

I also feel that SA, even more than CA, is why these F/5 achromats seem to be better suited generally to low and medium power magnifications. Of course there will be exceptions to this.

6 minutes ago, johninderby said:

Going from personal  experience you certainly can tell the difference between an FPL51 and FPL53 doublet at longer than F7. The FPL53  is noticeably sharper with better contrast. Not that the FPL51 is bad at all it just that side by side you would see the difference. 

Of course quality of the optics also plays a part but if the quality is equal there is that bit of a difference.

Yes, that matches my experiences as well.

23 minutes ago, banjaxed said:

The AZ3 mount and tripod are not really suitable for using the adaptor you are looking at. The adaptor you are looking at is for use on the steel legged EQ tripod tripod.  I have an AZ3 mount and rarely use it because I bought the 3/8" stainless steel tripod which will take most AZ mounts without the need for adaptors and is significantly more solid.

Having owned a few AZ3's I agree with this.

The way that the AZ3 attaches to the tripod top is not the same as other mounts. This webpage describes how to service the AZ3 and shows the mount base / tripod hub design:

http://www.spacegazer.com/index.asp?pageid=97491

I've owned and used Ethos eyepieces since they were launched. I'm not a glasses wearer.

I found the ES 92's harder to get used to re: eye positioning. I couldn't get on with the 12mm even after several sessions with it, so I let that one go in favour of the Ethos 13 which I'd owned for a few years. I like to have my eye nestled gently into the rubber eye cup to keep out stray light but with the 12mm ES 92 I could not do that without seeing black outs and holding my eye a few mm back from the eye cup I find less than relaxing as well.

The 17mm 92 is not as extreme in terms of eye position so I am gradually getting used to it. Its still not ideal for me though and I still find the Ethos the most comfortable though. 17mm is not a focal length that I use often (I tend to skip straight from the 21mm to the 13mm Ethos) so it is possible that I would let the ES 17 / 92 do at some point, despite it's excellent optical performance. I do also have the Delos 17.3mm in the 1.25 inch case and the 17mm ES 92 does take up a lot of "real estate" in the 2 inch eyepiece case !

I do think that the ES 92's are excellent eyepieces but for the non-glasses wearer, they can, for some, pose some challenges re: eye positioning. This may be down to some extent to facial ergonomics as well as the eyepiece characteristics.

I wanted to try them though, after reading such a lot about them so I'm glad to have had the chance to use both focal lengths in the range

I don't use a coma corrector either but my 12 inch dob is F/5.3. Coma is there but, personally, I don't find it intrusive even with 100 / 110 degree eyepieces.

Others do feel that is an issue though and use a CC even with F/6 scopes.

I've not owned an F/4.7 for a long time and when I did I didn't have any 100 degree eyepieces so I don't know how intrusive coma will be with such wide angled eyepieces.

I really like that "endless pool of stars" effect as well which is why I have always sought very wide field eyepieces. It's not everyone's "thing" though I appreciate that.

The ES 17mm 92 is probably the most immersive eyepiece that I have currently even though some of my others have an even larger apparent field. I guess it must be a combination of the massive eye lens AND the eye relief AND the 92 degree field that does it.

2 hours ago, Stephenstargazer said:

But it is a problem when using encoders and digital SC of course.

Yes, I can see that now you mention it. Not an option that I would be going for but I can see that you would not want to keep moving the tripod once it's set up.

21 hours ago, Space Hopper said:

Are the RA engineers going to introduce some sort of extension option at any point do you think ?

So the AZ100 can work on a Berlebach type wooden tripod with a longer refractor ?

 

I found my F/9.2 130 refractor worked OK without an extension in the main. Once or twice I needed to turn the tripod but not often. Or were you thinking of a longer frac than that ?

3 hours ago, Louis D said:

The ES-92 eyepieces have 20mm of advertised eye relief, but I've measured them at 17mm of usable eye relief.  This is just enough to use them comfortably with eyeglasses.  Many folks find it too much without eyeglasses....

I'm one of those people, unfortunately

I still have the ES 17mm / 92 though and that is better in this respect for me as a non-glasses wearer. The optical quality and immersiveness of the ES 92's is very impressive. They are pretty much as good as my Ethos eyepieces. The best ES eyepieces that I have used.

The downsides are that they are £400+ eyepieces currently and weigh a LOT !

With an F/4.7 scope though, coma is going to be an issue, unless @Size9Hex is planning on using a coma corrector ?

Collimation, as Mike says above, is not the issue here. You should see a decent image even if the scope is not collimated that well.

What we need to know is what you DO see though the eyepiece when you point the scope at a bright star or the moon using a low power eyepiece, that is the eyepiece with the longest focal length, eg: 25mm or 20mm or similar rather than 10mm, 6mm etc.

The most common issue with scopes not showing much at all is that the incorrect adapters are being used to hold the eyepiece so sharp focus is simply not achieved. This is why, again echoing what Mike says, a photo of your focuser with the eyepiece in place, as you have used it, will also help diagnose the problem.

Of course these scopes can and do work extremely well otherwise they would not be so popular

The more you study a target, the more you will see. Returning to it over several sessions often starts to reveal more detail as well. There is no rush - the Universe is not going anywhere

3 hours ago, Jasonb said:

So I've found out that the central bolt in this tripod is basically a 1/2 bolt, and obviously the mounts I'd be looking at are 3/8. Anyone any tips/advice on how to do a simple conversion? I think the bolt is used to help give the tripod some of it's stability, so not sure if a 'simple' bolt replacement would work...

The EQ3-2,EQ5, AZ4, Skytee II and HEQ5 use M10. The EQ6 uses M12. The AZ5 is 3/8th's I think.

I believe those Meade tripods have a flat top. The above mounts need a recess of 60mm or 30mm (depending on the mount) in the tripod hub to fit into.

Edit: The AZ5 can fit onto a flat tripod hub top I believe.

13 minutes ago, Stu said:

Lovely stuff John, very nice report. You are right about observing sessions being few and far between currently, so it’s good to read about any successful nights! I would love to see the Rosette nebula again, but I really don’t think my skies would allow it. Perhaps I’ll get the old Genesis out and give it a go once the Moon is out of the way again. Do you recall if it is any better with an OUII than UHC?

I've actually not tried an O-III on the Rosette Stu. I will next time out though !

It's a rather overlooked target for me to be honest - a recent thread on here put it back on my radar though

Another vote for the Powermate 2.5x here. I've owned a couple of them and the 2 inch 2x as well and they are totally invisible visually apart from the amplification you get.

A close alternative is the Explore Scientific 2x Focal Extender which has similar properties and performance to the Powermates at quite a bit less cost. 

I currently use a Baader Q-Turret with my Tak FC100 DL and that works well combined with a 7.2-21.5 zoom but I don't use the barlow with prime eyepieces so I don't know how it does with those.