miguel87

I really enjoyed M57 last night, best at 167x mag and some nice subtle detail in the outer shell. I have never seen colour or central star but it is a great nebula and so easy to find. I will have to try out the blue snowball, I have never observed this. I find the owl nebula M97 really dim. I view the eskimo nebula for the first time a few weeks ago and I teased up some detail but it wasn't easy. Definitely an area I want more experience in.

Entry level DSLR's dont come with 1000mm lenses.

Mounting an entry level DSLR on an EQ8-Rh would be overkill.

I think the problem is that most telescope mounts will be overkill for a camera and many camera mounts will not support a telescope. Entirely depends how big your scope will be because the mount needs to handle it. Any decent EQ telescope mount will manage you camera like it was a feather.

As you may have seen I have been posting my progress sketching the entire Messier catalogue. Last night saw another 5, taking my total to just 18 currently. M105, 96, 95, 53 & 57

Very nice, I like the balance of brightness without losing core detail. And wasn't it clear over swansea last night, wow! I sketched 5 messiers as part of my ongoing mission to sketch them all. Will post them up when I get a chance later this afternoon.

I definitely wouldn't put acetone on my coated lenses. I'm no chemist but it doesnt sound like a good idea to me.

Thanks guys, I will try another layer of parcel tape on the led and also try to commit more of the image to memory before adding to the sketch. Should get plenty of practice tonight as forecast is fantastic 🤞 Heading into the virgo bowl to tick off some messier sketches

Yeah, dont want to temp fate but tonight looks fantastic here 🤞🤞🤞

Sounds fantastic, nothing better than a successful night! I had my first look of this year at M13 on Sunday. Never fails to impress even in my 8inch newt. I'm sure you will get back into the swing of findings things. I have only ever used a telrad and depending how dark your sky it (I have a bortle 4 garden) it is all I need to find anything with my wide field eyepiece. Fingers crossed for more good nights soon ✌

If you have a polarscope in your mount it will be more accurate than having polaris centred in your telescope. You should be aligning the mount not the scope really. A pinhole eyepiece is useful for collimating tho. If we are talking about a goto telescope then I have no idea because I never owned one. I thought they did things mostly automatically tho?

Ok, this will be my last post I promise! Going right back to your original analogy of a small handheld mirror and a wall mirror. Let's imagine shining the moon off them onto a blank wall. Same brightness but one bigger patch of light. NOW, change the big mirror for 10 hand held mirrors, arrange them next to each other but angles so that they all reflect the moonlight onto the same patch of wall. Now both the single mirror and collection of mirrors are creating the same sized patch on the wall. BUT the collections of mirrors will create a brighter patch. Turn the collection of closely arranged mirrors into one smooth curved mirror and you have a telescope mirror. Collecting more light from the same object. Moonlight is falling all around you, on your telescope, on the floor, on your house and your entire street. You can scoop up as much of it as you like with a big enough mirror. You can't catch ALL the light off the moon in a handheld mirror! Even if you can SEE the whole moon. If that isn't the answer then I dont know what is. ✌

Interesting thanks, makes sense too. Thinking about the limitations and strengths of the human eye. I wonder if our average daytime aperture (maybe 3mm or so) is a sweet spot for detail? Surely we have evolved so that the part of the retina most often in use is the most effective. I guess it might be very task specific though and movement is probably more important that detail.

Totally agree with that! I feel a bit safer adjusting balance by sliding in slightly loose tube rings rather than moving the dovetail. Oh well, works for me!

Have I been making a mistake all this time? Speaking to a fellow astronomer today with a similar EQ newtonian. Realised he leaves his tube rings on his OTA permanently and just removes the dovetail from the mount. I always undo my tube rings and put the OTA in it's box on it's own. Am I weird?? 🤔

Wow, I never realised this. So a 4mm exit pupil has the same brightness in every telescope, binoculars, monocular etc??? This would just provide high mag in a 'big' telescope and wide field views in a small telescope? Interesting thanks! Does this mean that when looking for faint fuzzies, my lowest mag eyepiece should always be my first choice? But then naked eye would be at least as good? I guess we normally sacrifice some brightness for a bit of magnification.

Lots of people have given you the answer 🙂 Bigger area collects more photons and focuses them into an image. That's the basic, short version.

It does describe it correctly. The point source of a star is so far away that the incoming photons are parallel (like raindrops and not like a lightbulb). A bigger pan would catch more raindrops. Yeah...exactly, the bigger mirror catches more light.

Nice analogy, with the container of water being the camera or eyepiece.

Yeah they would fill to the same level so the pan would have lots more water in. Yes the shape is key, the light is being brought to focus. That's why you cant use your mirror as a telescope! There is no debating the fact that a larger mirror collects more light and shows dimmer objects. I upgraded from a 130 to 200 and the difference is VERY significant. Many objects that were invisible before are now easily locateable. Its the whole reason that your pupils dilate in the dark, bigger aperture.

But if you reflected the light off your two different mirrors onto a wall, the larger one would would show a bigger patch of light. Yes more light means more detail and dimmer objects. You are right that it is to do with the shape of the mirror focussing light to a point. Imagine positioning your eye at 100 different places on the mirror. You could see the same particular star from any of these positions. The starlight covers the whole mirror (this applies to every star within the view of the telescope). When focussed to a point you are therefore collecting a brighter image. The same as a tea cup vs a saucepan catching rain. Field of view is not dictated by aperture. Hope that sort of makes sense?

Visual polar scope and polar finder phone app 😁

Great first sketch. Can I ask how you turned only the FOV negative? Looks smart that way 👍

Thanks for your kind comments. I am finding it a really rewarding experience and I hope that when nearer completion it might provide a realistic idea of what can be seen in an average (I think) sized scope under good/average skies (bortle 4) without the aid of filters cameras EEVA or anything else. 😁

I wonder at what magnification a star starts to dim? I always ask to many questions and then never understand the answers 😂