davhei

20 hours ago, Martin Meredith said:

I also love reading up on objects. This is what I sometimes do: 

1. Go to Simbad: http://simbad.u-strasbg.fr/simbad/

2. Type in the name of the object in the Basic Search box. This brings up some basic info on the object.

3. To find out more, scroll down to References and press the button marked 'display'. This brings up much of the known literature in which the object is mentioned, most-recent first. You need to be a bit selective here, but it can be interesting to look at the earliest such reference as well as some of the most recent.

4. To find out about a specific reference,  after clicking on the title (which brings up an abstract), the best option is 'view the reference in ADS' (near the base of the page). 

5. Once that page comes up, nearly always you'll find a free pdf on arXiv (link on the right go the page). Often going to the publishers website you get the abstract only.

Hope this helps!

Martin

 

That's a brilliant suggestion Martin, couldn't have asked for anything better really. Thanks for posting!

On ‎11‎/‎02‎/‎2020 at 01:48, John said:

Lately I've been enjoying observing relatively straightforward targets such as open clusters and double stars etc and then finding out more about them, when they were first observed and by who, theories and discoveries relating to them, quirky information etc, etc.

Armed with a little bit more information, a familiar target seems to take on a whole new level of interest I find

Reading old accounts by well known (and not so well known) historic observers then examining the subject with your own instrument and eye is also absorbing.

 

 

John, do you have a favourite source for reading up on objects? Wikipedia is a treasure trove but I was just thinking if you had something specialised.

Welcome Tom, look forward to seeing some of your imaging work if you feel like sharing.

It is really fun to read about how people get a sense of wonder and excitement when engaging in our common hobby. Does make me appreciate how special the experience can be and encourages going back to an object to reflect on what we are actually seeing.

Oddly enough, and perhaps fortunately considering the limitations of visual astronomy, the less striking objects are often those that have stuck with me the most. I recall vividly the profound feeling of space and time when seeing a few photons from a distant quasar. Objectively speaking not much to look at, only a flicker of light when using indirect vision, but the realization that light emitted billions of years ago from the accretion disk of a black hole was destined to be absorbed by my retina in a different part of the universe almost made me fall off my observing chair. The feeling of getting a glimpse of a vast reality beyond the limited point of view that we usually have. It can be like a spiritual experience, and that feeling doesn't come around all that often.

Welcome Seb!

Welcome Derek. Enjoy your re-discovered hobby!

I'll give the Pan 27 a go since one came up for sale. Be interesting to compare the 24 and 27 and decide which one stays.

Cheers

2 hours ago, TheLookingGlass said:

The best low power eyepiece w/o a coma corrector, in a 10" f/4.7 is the 22mm Vixen / Orion LVW. Try looking for a used one on the used market. 

Cheers!

Thanks! Do you know the differences between the Vixen and the 22 mm T4 Nagler? I would assume there would be similarities and the Naglers are always held in high regard. Do the Nagler need coma corrector to get sharpness across the full field while the Vixen albeit with a smaller tfov has sharp stars almost to the edge?

Welcome to the lounge neighbour! Let’s hope for some clear nights ahead, way too much cloud these past months.

1 hour ago, Davey-T said:

May set fire to the paper 

Dave

Would make me look a proper pro wouldn’t it. Some boffin playing with binoculars and setting everything on fire.

😁

Could I hope to see anything by projecting on a piece of paper or cardboard through 8x42 binos without filters?

And importantly, could I damage the binos by doing so? Wouldn’t want to crack a lens or soften up interior cementing or the like.

1 hour ago, mikeDnight said:

Baader Morpheus are superb and the 17.5mm will give you a spectacular high contrast view with a nice dark sky background. 

Thanks! The tfov will be pretty close to my limit where I start to get lost when starhopping though. Will have to try and see how narrow a field I would be ok with. Given that this would be my higest focal length EP I would like a bit larger field of view.

Welcome to SGL. Enjoy the scope! Sounds like you have the possibility of really dark skies not too far away.

Another viable option could be the ES68 24 mm. Longer eye relief than the Pan but perhaps a bit less well corrected, heavier, but still light of course. Doesn’t hurt that it gives some cash to spare.

7 hours ago, niallk said:

The Pan24 was my choice for my 10" f4.7.  No balance issues... just trim your eyelashes!! 

I thought about it but I would never hear the end of it from my wife 😆

10 hours ago, John said:

Getting eyepieces that are wide, well corrected at F/4.7, have decent eye relief and are light in weight is a tough order. To get the well corrected performance at fast focal ratios and good eye relief, quite a lot of large glass elements are needed with some radical curves on them and those are what weighs the most of course.

Of those discussed here, I've owned the Nagler T4 22mm and thought it a very good performer and comfortable to view though. 

I now use the Ethos 21 and a Nagler 31 but those are definitely in the heavyweight category.

 

 

Yes the 22 T4 Nagler keeps coming up, would love to try it out. Perhaps pick it up on the used market and compare it to the Pan 24 for a while, see which one (if any) comes out on top for me.

I guess somewhere down the road I’ll arrive at a point where I can better understand what aspects are most important to me and which ones are easier to make compromises on.

At the moment I think comfortable viewing and good correction across the visible field trumps tfov. Pincushion would be ok. Not keen on having to add a paracorr because of the cost and added weight.

I have heard many state you ”need” a paracorr with the 22 mm T4 Nagler in fast scopes but I think that would push the total weight to over a kilo.

If the Pan 24 just had better eyerelief I think it would be a nice fit. With that said, since I haven’t put it through its paces properly yet I shouldn’t be so quick to judge. Perhaps I’m exaggerating the problem. The process of choosing is pretty fun though.

48 minutes ago, Louis D said:

The 20mm APM HDC XWA is only 24 ounces, 12 ounces lighter than the 21mm Ethos and the same as the 22mm NT4.  According to what I've read, it's better corrected than the 20mm ES-100 and not that far off the 21mm Ethos.  Eye relief is 15mm designed and 12mm-13mm usable.  How much eye relief do you prefer when using eyepieces?

I’ve never looked at Lunt EPs before, certainly never through them. Have heard them mentioned a lot though so worth considering for sure. Thanks!

As far as eye relief goes, no less than 15 if there is to be no lens contact, more would be even better. ES 82 30 mm is listed as having over 20 mm and that felt good. Delos as well obviously.

7 minutes ago, kev100 said:

Hiya. If you're not too bothered about a little coma, and it's just for star hopping/finding objects, how about using a 0.5x focal reducer? I too have a fast 10in scope, and sometimes pop my (admittedly pretty cheap one) on my 16mm 68 degree ES MaxVision (turning it into a 32mm EP). The view is actually pretty reasonable.

Kev

 

A focal reducer, that’s interesting. Never thought of that Kev, thanks. What are the drawbacks of those? I’ll have to read up a bit I think!

Thanks Louis, much appreciated!

Problem with the 31 mm NT5 and I guess Ethos 21 as well is the weight. Just unbalances my scope too much att certain angles. I would trade some tfov for a lighter EP. With Ethos there’s the question of eye relief as well.

Realise I may have to compromise with a few things, no such thing as a perfect ep I guess.

Hi all,

Have been pondering low power eyepiece options for some time and would really appreciate some good input.

A few parameters:

I’m using a 10” f4.7 dob without paracorr.

As this will be used to find objects by star hopping I believe I need a minimum tfov of around 1.3 degrees.

Have had balance issues with EPs weighing in at 1 kg so it needs to be lighter than this.

I do not observe with eyeglasses but have long eyelashes and would like more than 15 mm eye relief if they are not to brush against the glass.

Good contrast. Compared the ES 82 30 mm to the ES 68 24 mm and the difference in contrast was striking. Really appreciated that.

As well corrected as possible. I am not hyper sensitive to coma though.

Have had an ES 82 30 mm and tfov was great. Weight, contrast and off axis less so.

Just got a Pan 24 that might be a good match, eye relief causes some concern though and I need to evaluate it a bit more (when I get clear skies, sigh).

Pan 27?

22 Nagler?

The other EPs in my case are Delos 14, 10 & 6 mm plus a x2 TV barlow. All of these are great, it’s the low power finder EP that I need to nail.

On ‎29‎/‎09‎/‎2019 at 19:29, cloudsweeper said:

Good points Marvin.  We're all different in our wishes and expectations of course.  As for me, the memories are sufficient, and although non-astro folk care not a jot for faint grey fuzzy patches, they really "do it" for us visual-only astro fans.  I captured galaxy NGC 772 a few days ago, and was awestruck by what I was observing - a galaxy twice the size of our Milky Way.  In my eyepiece.  Fantastic!

Doug.

Having never done any AP (yet), sticking to visual only, it is interesting to consider what makes an impact on me when observing through the eyepiece. A number of occasions come to mind, seeing Jupiter in high magnification revealing cloud bands and the galilean moons, the veil from a dark site, crisp lunar vistas with long shadows.

Oddly enough, and perhaps fortunately considering the limitations of visual astronomy, the less striking objects are often those that have stuck with me the most. I recall vividly the profound feeling of space and time suddenly becoming clear in my mind when seeing a few photons from a distant quasar. The realization that light emitted billions of years ago from the accretion disk of a black hole was destined to be absorbed by my retina in a different part of the universe. The feeling of getting a glimpse of the vast reality beyond the limited point of view that we usually have in our daily lives. Of our place in the universe. Truly a spritual experience. That feeling doesn't come all that often, but when it does it stays with me and is certainly part of the fascination I have with observing the skies.

That is an absolutely magnificent sketch. Did you use ink? The stars look jet black and very rich in a pleasant way.

Sure you will make many more great sketches if you continue like this. Really adds another dimension to observing, go for it! 

Edit: Right I see the pencil now, nevertheless a nice deep look to those stars.

6 hours ago, MaHa said:

Hi davhei, 

Can I ask how you invert the colours please, making the sky black and stars white? I'm a total novice at sketching so my knowledge is very limited! 

Many thanks, 

Mark 

I use an app on my phone. There are probably many out there but I use pixlr.

I first snap a picture of the sketchpad, preferrably in overcast daylight, then adjust the colours to zero on the phone image editor to get greyscales. Load the image into the app, make a few adjustments to contrast and then invert the colours.

A more ambitious person could probably work miracles in photoshop but sadly I am not one of them. 😀

6 hours ago, Littleguy80 said:

I just wanted to follow this up to say that I managed to observe this tonight from my dark site. It was quite tricky. I actually used your sketch as a means of confirming that I’d found it! It’s surprising how far from the core of Andromeda this is. 
This was the highlight of my session tonight so thank you once again for posting your excellent report and sketch  

Fantastic! Makes me very glad that I was able to inspire and that the sketch actually helped. In general I have found that people’s sketches at the eyepiece are a great aid for visual observation, perhaps more so than images of the same object, simply because they provide good references for fields of view and magnitude of visible stars.

33 minutes ago, Ruud said:

Yes, it would look nice if you did that with your star sketches. You should try the freeware GIMP.

I imagine this is how it would work in GIMP: open your scan or photo. Add an empty layer, change its blend mode to colour and paint an orange blob on the empty layer over Arcturus. Anything underneath the blob that is not black or white will take on the colour you used.

I did this in Photoshop using a rather tacky highly saturated orange-red for Arcturus:

The orange blob is bigger than the star, but that does not matter because black and white are not affected.

I should add: the original was a grey scale image, so my first step was to convert it to RGB colour.

Some search terms to help you find the right tutorials: GIMP change image mode to RGB, GIMP add new layer, GIMP change blend mode of layer, GIMP save as png.

Good luck. Get GIMP and get going. It is an excellent tool for this task.

That’s an awesome suggestion and a what a tutorial! Thanks for this Ruud, much appreciated!