Gear recommendations/advice for newbie

[LoveFromGallifrey]

So, I'm looking to build up a little equipment base through which I can begin delving into imaging and processing. But I'm clueless. I want to image mainly DSOs and lunar with the potential to branch into solar, since I don't know if my scope lends itself to planets very well. 

What I have already: 

- Altair Asteo Starwave 102ED-r doublet with FPL53 

- Altair Raci 60mm 90° finderscope 

- EQM-35 

- Nikon d3400 

So, I know that I'll need a T ring adapter for the DSLR, and from seeing other people's setups I'm vaguely familiar with flatteners...but I've also had people tell me a flattener isn't necessary? I've also had people mention needing spacers but I have zero idea about that. People have warned me that my camera body is pretty poor, and that it will be very difficult to focus. Is this true? 

Another thing I was considering doing is investing in a small, cheaper dedicated astrocam with the potential to be used for guiding as well. I'm not looking to break the bank or rival Hubble, nor am I even really looking to equal any other amateur imaging astronomers. I'm looking to build my experience in operating a dedicated cam, while experimenting with imaging. 

So...what does everyone think? Any ideas, advice, recommendations? Basically feel like climbing on the roof and crying for help whenever I start looking at this stuff 🤣

Edited January 5, 2021 by LoveFromGallifrey

[rickwayne]

Lunar is pretty easy relative to DSO, since the Moon is a daylight target. But also relatively small, there are quite a few DSO targets much bigger than the Moon.

The thing about deep sky is that the objects are dim, requiring long exposures or lots of them or both. But if your ambitions are modest, I think you can get something you like.

Your mount has a stated payload capacity of 22 lbs.;  standard practice for astrophotography is to load the mount to no more than half capacity. You will just squeak under that, I think.

Your scope is also pretty long at 700mm and pretty dim at f/7 for a beginner's DSO tube. Focal length magnifies any mount imperfections, and a higher focal ratio requires longer exposures, making it harder still to get sharp pictures.

A flattener is necessary for almost any scope, if you want edge-to-edge in-focus images. The focal "plane" for both refractors and reflectors is in fact a curved surface. And since the zone of critical focus is measured in microns, it doesn't take much curve to make it impossible to get both center and edges in focus. Flatteners unbend the focal surface, but only at a very specific distance (you may have seen the term "back-focus").

Even more attractive, if you want to do DSOs with that scope, is that frequently flatteners are combined with reducers, sort of a negative magnification lens that concentrates more of the light coming  from the objective onto a smaller image circle. A field flattener/reducer would make your scope a bit less long and a bit brighter, simplifying your problems getting good tracking performance out of a low-cost mount. Frequently FF/Rs have a backfocus such that the T-ring and bayonet adapter for a DSLR puts the sensor just at the correct distance; 55mm is the standard.

Absolutely crucial: Buy and read one of the basic astrophotography books. I totally feels you WRT roof-crying! There are so many options and tradeoffs that it's really hard to know where to start without wasting tons of money trying to jam together gear that Mother Nature never intended to be together. I cannot speak to lunar or solar photography, but here are three very-well-regarded books for DSO:

• The Deep-Sky Imaging Primer by Charles Bracken
• Making Every Photon Count by Steve Richards
• A Beginner's Guide to Astrophotography by Jerry Lodriguss

Seriously, if you don't smack your forehead and mutter "Oh, so THAT'S what they were talking about" at least six times while reading any one of these, I will give you back the price of this post :-). Bracken's was/is my bible, he builds you up from basic concepts to the gear and techniques that stem from them, with gear selection, capture technique, and processing all covered.

Welcome, and as I often say, I wish you joy in the journey! To calibrate your expectations, I'll leave you with a quote from a Texan visual astronomer I encountered in the Bortle-1 Big Bend National Park: "In my experience, an imager is a guy standin' there in the dark swearin' at something that ain't workin'".

Edited November 29, 2020 by rickwayne

[LoveFromGallifrey]

This is a ridiculously late reply to your post, so I'm sorry for that (and sorry for dragging my own post back up from wherever it was buried). 

But I had to come back and say a massive thank you for your advice. Its so sound, and has been a ridiculous amount of help. I've invested in a copy of the Deep-Sky Imaging Primer as a belated Xmas gift to myself, and I shall study it religiously. 

I haven't yet purchased anything else for my setup, because I want to read the book first. No use rushing into things, as you say - my biggest fear is buying the wrong things and wasting money. I have a working plan to purchase the flattener/reducer made by Altair to suit my scope, and have copped a glance at a couple of guide scope/cam options, but that's about as far as I have gotten right now. 

I think the difficulty is with my scope, as you say, it's probably not a great choice for imaging in the first place and especially not with my mount. I tried to find something decent enough for portable observing (have successfully taken it across the country, on a plane, used it in the middle of nowhere etc) but also not too impossible to use for imaging. Its a difficult balance for anyone to get right, and especially a dumb beginner like myself! The mount is the best I could find in the current circumstances. Fully intending on upgrading once I have the option. 

And finally, thank you again! I love that quote, that already sums up my experiences - from polar aligning the darned mount (I cannot see Polaris from my house...at all) onwards. It only gets more confusing haha! I'm having fun though, and cultivating a rather impressive of bad language to use on demand :D 

[rickwayne]

Awww! You're very welcome! The kindness of strangers is certainly the only reason I've been able to have any success at all in this.

[alacant]

On 29/11/2020 at 20:18, rickwayne said:

a higher focal ratio requires longer exposures

Mmm. I often wonder about that. I tend to think not.

Maybe worth checking.

Cheers

Edited January 8, 2021 by alacant

[rickwayne]

At the risk of re-re-re-reigniting the Ancient Flamewar, if you're imaging deep-sky objects, for the same sensor, an f/2 scope will require fewer seconds to get the same number of electrons in the photosite well than will an f/5 scope, regardless of aperture. Honest. See Bracken, page 38.

[alacant]

Read all I may, I've never understood this. It depends on f-ratio. So my 72mm f6 skywatcher will capture the owl nebula faster than the 2 meter f10 telescope at La Palma? 

Edited January 9, 2021 by alacant