1. Choosing images

What deep sky objects to image depends on the season, the location, the phase and position of the moon, and any obstructions from, e.g., trees or buildings. The weather and clear skies are obviously paramount. Winter tends to be better than summer for many objects and winter nights are longer (and mosquito-free!).   

Charles Bracken’s Astrophotography Sky Atlas and Astrophotography Planner are key to identifying objects. Antoine and Dalia Grelin’s monthly emails (Galactic-Hunter) are very helpful. I consult the Night Sky Observer’s Guide by George Kepple and colleagues, appropriate volumes. Finally, I use Starry Night pro to check the observability of the chosen object.

With planets and the moon, I simply use Collins’ annual guides to the Night Sky, southern and northern hemisphere editions.  

2. Choosing and purchasing equipment

Choosing, purchasing and setting up equipment has been a long and difficult process, with much guessing and trial and error. Many astrophotographers have helped, including (in alphabetical order), but not restricted to: Riccardo Cappellaro of Teleskop-Service Ransburg GmbH, Trevor Jones (AstroBackyard), Wido Oerlemans (Wido’s AstroForum), Cody Peterson (AstroBlender), and Chris Woodhouse (book).

3. Stand-alone set-ups

My main approach is to have stand-alone set-ups for different types of imaging that only need to be placed on the mount. Thus, each set-up has its own:

• Scope or lens
• Guide scope
• Dew heaters
• Cables and cable management clips and holders
• Adapters and spacers for correct backspace
• ZWO Electronic Automatic Focuser (EAF)
• ZWO ASIAIR Plus controller
• USB hub
• Extender cables connected to ASIAIR Plus for connections outside the set-up (ethernet cable, mount cable, and, for CGEM mount, hand controller cable)

Although this approach is not resource constrained, I adopt it for the following reasons:

• Ease of use
• Ensures correct adapters, spacers, cables and cable management are in place

The items that I change are:

• The trains for imaging deep space objects (those outside the solar system)
• The trains for imaging objects within the solar system.

4. Common equipment

Original Celestron CGEM mount, tripod and counterweights, TS-Optics Adaptor Saddle Clamp from Losmandy to Vixen style to mount smaller scopes on CGEM mount, ADM Vixen-type Dovetail on top of EDGE HD 9.25 to mount guide scopes (southern hemisphere site).

TP-Link Deco X50-Outdoor attached to mount, with wireless connection to Deco mesh inside house (southern hemisphere site).

ZWO AM5 mount and carbon fibre tripod with pier extension and counterweight (northern hemisphere site)

Wired connection from ZWO ASIAIR Plus controller to deco mesh inside house (northern hemisphere site).

TeleGizmos 365 Scope Covers to protect against sun and rain.

Lenovo Tab Extreme as interface with ASIAIR Plus controller.

USB pen drive connected to USB hub to store images for easy transfer to computer.

5. Deep sky imaging, mid-focal length (this is the one I use the most and is the easiest option)

Usually take 30 images with each filter, 300 seconds for Ha and 450 seconds each for SII and OIII. Often, have to do this over two nights. For calibration frames, take darks of same length as lights (using dark filter in filter wheel), flats with automatic exposure, and flat darks of the same exposure as the flats.

RedCat 71 APO (older version, without WIFD focuser, and using Black-CAT Mount to connect ZWO ASIAIR Plus and EAF) with ZWO ASI 2600mm, ZWO electronic filter wheel, ZWO 7nm Ha SII OIII Narrowband Filter Set, William Optics UniGuide 32mm as guide scope with ZWO Camera ASI 174 MM Mini Mono as guide camera (southern hemisphere site).

Pleiades 68 astrograph with ZWO Camera angle adjuster (CAA), ZWO ASI 2600mm, ZWO electronic filter wheel with Baader 6nm Ha, SII, OIII Narrowband Filter Set, ZWO 30mm Mini Guide Scope (better in my view than William Optics UniGuide 32mm), with ZWO Camera ASI 174 MM Mini Mono as guide camera (northern hemisphere site).

6. Deep sky imaging, long-focal length (technically more difficult when using EDGE HD)

Usually take 30 images with each filter, 450 seconds for Ha and 600 seconds each for SII and OIII. Often, have to do this over two nights. Calibration frames as for mid-focal length.

EDGE HD 9.25” with ZWO ASI 2600mm, ZWO electronic filter wheel, ZWO 7nm Ha SII OIII Narrowband Filter Set, TS-Optics 70 mm f/6.78 ED 4-Element Flatfield Refractor Telescope mounted on top of EDGE with guide scope rings (to align) as guide scope, with its own ZWO EAF and ZWO ASI662MC Camera as guide camera (southern hemisphere site).

TS CF-APO 130mm with Wega Adapter for ZWO-EAF,  ZWO ASI 2600mm, ZWO electronic filter wheel, Baader 6nm Ha, SII, OIII Narrowband Filter Set, William Optics Zenithstar 61 II APO as guide scope with its own ZWO EAF and ZWO ASI662MC Colour Astro Camera as guide camera (northern hemisphere site).

7. Deep sky imaging, short-focal length (technically more difficult with processing)

Usually take 30 images with each filter, 120/180 seconds for Ha and 240/300 seconds each for SII and OIII. Calibration frames as for mid-focal length.

Sigma ART 85 mm lens attached to Astroprints EAF motor mounting kit (very good, but flimsy and readily breaks), with  ZWO EOS thin lens adapter for 2“ EFW Filter wheel (to ensure 44mm back focus), ZWO electronic filter wheel,  ZWO 7nm Ha SII OIII Narrowband Filter Set, William Optics UniGuide 32mm as guide scope with ZWO Camera ASI 174 MM Mini Mono as guide camera (southern hemisphere site).

Sigma ART 35 mm lens with home made mounting kit for EAF (specifications available on request), ZWO EOS thin lens adapter for 2“EFW Filter wheel (to ensure 44mm back focus), ZWO electronic filter wheel with Baader 6nm Ha, SII, OIII Narrowband Filter Set, William Optics UniGuide 32mm as guide scope with ZWO Camera ASI 174 MM Mini Mono as guide camera (northern hemisphere site).

8. Lunar imaging

I use same set-up as either mid- or long-focal length deep sky imaging, but with Baader LRGB Filter set or ZWO LRGB filter set and ZWO ASI462MM USB3.0 Mono Astro Planetary Camera.

I usually take up to ten one-to-two-minute AVI videos, high resolution, with the video module, of ASIAIR Plus

9. Planetary imaging

Planetary imaging has been guided by Christophe Pellier and colleagues (Planetary Astronomy Book).

The trains are as follows:

EDGE HD 9.25” → FTF Starlight Adapter → Starlight Instruments Feather Touch Focuser (with EAF attached) → Televue powermate 2.5 Barlow → ZWO Electronic Filter Wheel with ZWO LRGB filter set → ZWO ADC Atmospheric Dispersion Corrector → Planetary camera, ZWO ASI462MM.

TS CF-APO 130mm → Televue powermate 5.0 Barlow → ZWO Electronic Filter Wheel with Baader LRGB Filter set → ZWO ADC Atmospheric Dispersion Corrector → Planetary camera, ZWO ASI462MM

I attach a Mele mini-PC with Velcro to either scope, connected with ethernet cables as for ASIAIR Plus, and loaded with FireCapture that is remotely controlled with Remote Desktop Connection by my home computer.

One-to-two-minute videos are captured for each filter either as AVI files, high resolution, with the video module of ASIAIR Plus, or as SER files with FireCapture.  Although it is more complicated, SER files seem to give better results than AVI files.

I have also experimented with ZWO Camera ASI 678 MC Colour and have obtained as equally good images as with the ZWO ASI462MM.

10. Solar Imaging

Solar imaging has been guided by Christian Viladrich and colleagues (Solar Astronomy Book).

The train is as follows: William Optics Zenithstar 61 II APO → William Optics Adjustable Flattener → Astronomik UV+IR Blocking Luminance Filter → William Optics Dielectric Diagonal → DayStar Eyepiece Holder → Daystar QUARK Hydrogen Alpha Solar (Chromosphere) Filter → DayStar 0.5x Imaging Focal Reducer → DayStar Interference Eliminator → 30mm spacer (to further reduce size of image) → 10mm camera adapter →  ZWO ASI 432MM USB3.0 Monochrome Imaging Camera

It can be surprisingly difficult to find the sun – here, accurate polar alignment is essential.

I usually take up to ten one-to-two-minute AVI videos, high resolution, with the video module, of ASIAIR Plus

11. Some conclusions from the experiences that I have had

• Align piggy-backed scopes: For guide scopes that are mounted with rings on other scopes, it is essential to very accurately align all scopes. This is best done during the day, and where visible, I find cranes or electricity pylons the best objects.

• ASI2600MM Duo: I tried using the ZWO ASI2600MM Duo that combines imaging and guiding sensors in one camera body, but I considered that a separate guide scope guided better.

• Calibrate guiding: When setting up new observing equipment, it is essential to calibrate the guide scope. This can be done with the ASI AIR Plus, aiming for 10-15 steps per axis – if too few steps, the calibration step value should be decreased; if too many steps, the calibration step value should be increased; the higher the focal length of the guide scope, the smaller the step size.

• Calibration frames: Taking calibration frames, although time consuming, is essential – images are certainly improved.

• Clamps and bars: I find it difficult getting the correct clamps and bars. Suppliers help in the choices as well as trial and error.

• DOLLY: I used to use a dolly for my CGEM mount and tripod but found this too cumbersome and unnecessary. I just use muscle power to move the mount and tripod.

• EDGE focusing: I find focusing with the EDGE HD 9.25 and attached ZWO EAF difficult – but, with much patience, it works – the advantage of the EDGE HD with its large focal length in a relatively compact and not too heavy scope outweighs the difficulties.

• Future investment: I would like to replace my now old CGEM mount with the ZWO AM7 mount, placing this on a new Celestron heavy duty tripod that, with an appropriate-sized metal rod, seems possible. This would give better stability than with the lightweight ZWO tripod.

• Guide scopes: For my large scopes (Celestron EDGE HD 9.25, and TS CF-APO 130mm), I mount appropriate focal length smaller telescopes as guide scopes. I find that this is much easier and as good at guiding as using off-axis guiders.

• Inventory: I keep a detailed and accurate inventory of all equipment in both sites – otherwise, I forget what is where, and the inventory is useful if I need to re-order.

• Monochrome cameras: I only use monochrome cameras. I have some good quality one shot colour cameras (e.g., ASI 2600mc), but I find consistently that acquired images are of substantially better quality with monochrome cameras and appropriate filter use. The one exception to this is that planetary imaging can work well with the ZWO ASI 678 MC camera.

• Note taking: I keep detailed notes of instructions – as these are easily forgotten.

• Pleiades 68: I find the Pleiades 68 astrograph a dream, despite written concerns about it. It is easy to set up and use and provides perfect images.
• Polar alignment: accurate polar alignment is essential either using ASIAIR Plus Polar alignment feature or All Sky Polar Align, when north or south celestial poles are obstructed.

• Set up during daylight: Getting everything ready during day light is much easier, avoids stress and mistakes when hurrying during night time and ensures image capturing is ready to go as soon as it is dark.

• Spacers locking: I have trouble with spacers and adapters locking – I ease this by using Bicycle Chain Wax, lens wrenches and thread openers.

• Tool sets: I have complete sets of small tools, hex wrenches and nuts and bolts to manage all the engineering sides of the equipment.

• Use ASIAIR Plus Plan:This ensures that you are ready to image at the click of a button. I revert to autorun in case of any difficulties.

• ZWO ASI 2600mm screwed: to ZWO Electronic Filter Wheel with 5mm rim removed.

• ZWO Carbon fibre tripod: I find that the ZWO carbon tripod used for the AM5 drive that I have is much too light when loading (it is fine once loaded). If I am mounting the TS CF-APO 130mm, I have to get my son to hold the mount steady.