Having been given a nice wide SharpStar 61EDPH2 telescope to review, as well as a ZWO ASI183mm Pro – a cooled mono camera – I thought I’d love to try a SHO image again. After having a browse about in Stellarium, I decided I was able to frame up the Tadpoles, Spider and Fly nebula. So with clear nights being in short supply, I set to work.
The Tadpole Nebula
The Tadpoles nebula, IC 410, is located within the constellation of Auriga. This constellation also features another notable target: The Flaming Star Nebula. The Tadpole Nebula is located, galactically speaking, right next to the Flaming Star. As such, finding it is quite easy for photography. It’s an emission type diffuse object though, so viewing it (especially under light pollution) isn’t an easy feat.
Located 2185 light years away, the Tadpoles Nebula is also regarded as a cluster associated with nebulosity. On Stellarium, the Letter Y cluster is located within the centre of the nebula. Another well known nebula like this is the Rosette Nebula. The best information I can find is that IC 410 is a magnitude 10 object. However I tried to view it myself with 15 x 70 binos (which should be good enough) and couldn’t even see a faint fuzzy.
Normally I focused my time on the Flaming Star Nebula. But I thought I really wanted to give this one a go. I’ve seen people sharing their IC 410 images before and Trevor Jones at AstroBackyard managed to score an APOD with his photo of it. So I set the gear up, and began planning.
The Gear
For this image I let loose some new toys. These included a SharpStar 61 EDPH2 Triplet Apochromatic refracting telescope. As well as a ZWO ASI 183mm. That’s a cooled monochrome camera. This was paired with Optolong SHO filters in an electronic filter wheel. I used my trusty EQ6-R Pro mount, and it was all controlled by the ZWO ASI Air Pro.
SharpStar 61 EDPH2
As mentioned the Sharpstar 61 is a triplet apo telescope. This means it has three elements, one of which is an ultra-low dispersion element (ED). This really helps improve colour correction by bringing all wavelengths of light to the same place. All this does is help remove chromatic aberration. Which is an absolute bane to lens users.
The entire telescope is a tiny little package. It’s really wide – 335mm focal length f/5.5. Even with the dew shield extended, the whole scope is easily portable and very light.
Key Specs
- 61mm Aperture
- Three multi-coated optical lenses
- Retractable Dew Shield
- 335mm Focal Length
- F/5.5 – Easily suitable for deepsky imaging
- Finder shoe
- 1.9kg (4.18lbs) with rings and dovetail
It was easy to focus this telescope also as I had a bahtinov mask which fit my old Sky-Watcher Evostar 72ED Pro telescope. This just attached right on the end of the dew shield and made focusing a breeze. On top of that the focus tube is fully indexed.
I also had the 0.8x Reducer/Flattener for this telescope. That made this scope even wider, and faster. With the matched SharpStar 61 EDPH2 Reducer/Flattener it brings the telescope to 275mm focal length f/4.5. Blazing speeds.
ZWO ASI 183mm Pro
A cooled monochrome camera is, to some, the gold standard when it comes to deep sky astrophotography. Amazingly, I’m not new to using a mono 183 sensor. I previously used the Altair Astro Hypercam 183m ProTec camera. Though after some time with the ZWO version, I actually prefer it. That isn’t just because I enjoy ZWO. But so far I’ve found the camera to be more responsive, and the amp glow to calibrate out nicely with DeepSky Stacker. A problem I continually faced with the Hypercam. As such, I would choose the ZWO.
It has a small chip. 13.2mm x 8.8mm. This gives for a narrow field of view when teamed with such a wide telescope. But the smaller chip, theoretically, uses the very best piece of the glass. You probably wouldn’t even need the flattener with this sensor.
Key Specs
- 12 Bit ADC
- Cooled – up to -40’c below ambient
- 13.2mm x 8.8mm sensor
- Approx 20.18 megapixels!
- 2.4um Pixels
- 5496 x 3672 resolution
- USB 3 main port, 2x USB2 hub on camera
- 15ke Full Well
- 1.6e @ 30db Gain read noise
Optolong SHO Filters
The filters supplied to me from First Light Optics for review was a full compliment of LRGBSHO filters. But in this instance I, as mentioned, used the Hydrogen Alpha, Sulfur-II and Oxygen-III filters.
Hydrogen Alpha
- 7nm Bandpass
- 31mm Diameter
- IR Blocking
- 2mm thickness
- 80% Transmission
Oxygen-III
- 6.5nm Bandpass
- 31mm Diameter
- IR Blocking
- 2mm Thickness
- 95% Transmission
Sulfur-II
- 6.5nm Bandpass
- 31mm Diameter
- IR Blocking
- 2mm Thickness
- 95% Transmission
Using The ZWO ASI Air Pro
I was given the ZWO ASI Air Pro to make good use of all this ZWO equipment I was loaned. The ASI Air Pro is a small computer that rides on the telescope and can control the camera, focuser, filter wheel and mount. You can use it for Go-To and platesolving, meridian flipping, live stacking, full auto-run imaging plans and guiding. As such, it totally replaces the laptop.
It also has output power ports on it, enabling me to ditch so many additional plugs. All I had to do was power the ASI Air Pro and plug the other equipment into that for power. Then the cameras, mount etc connect via USB to the Air Pro. It’s all then controlled by an Android or iOS app.
A full review of all this gear will be coming. I also have a Sky-Watcher EQ6-R Pro Review already.
Capturing The Tadpoles Nebula
The stage was set. The night was (sort of) clear. I set up all the gear, and got to it. After polar aligning with the ASI Air Pro (fantastic just so you know). Slewing over to IC 410 I began framing up. I decided to go for multiple targets in one frame. I could get the Tadpoles Nebula, Spider Nebula and also the Fly Nebula.
Unfortunately I really messed up the rotation over the several nights I imaged. The two nights and a bit that I photographed this cluster of DSOs, I had three different rotations. Also different locations. I had saved a custom location in the ZWO ASI Air but for some reason I just messed it up.
The Imaging Plan
So with the targets sorted, the framing decided and the equipment setup. It was on to sorting out how long to shoot for. The temptation of doing extremely long photographs. In my Soul Nebula I was shooting 15 minute exposures. I decided to not go this far. I chose a nice modest 5 minutes. The problem I faced? Cloudy forecasts.
I only had a couple hours on the first night before clouds were forecasted. So I decided to go for a simple one-hour intervals. 12 x 5 minute goes between each filter. Beginning with Hydrogen-Alpha. It was about half way through the OIII filter before the clouds set in. So I had to wait for a few more nights.
Eventually, I was able to finish this project. The final image contains 19 Hydrogen Alpha images, 31 Oxygen-III images and 29 Sulfur-II pictures. I wanted to get more Hydrogen-Alpha really. But alas the signal is so much stronger than OIII and SII.
The Final Image
I spent some time editing this. For some reason I really struggled to create a Hubble Palette with this dataset. I’ve made them before but this one proved difficult. However I stuck with it and ended up with an image I really enjoyed. Maybe I will add more data to this in the future, but since this equipment is rental, I need to get as much as I can on lots of different targets.
I hope you enjoy the image. I have a video on my YouTube channel also vlogging that evening.
As always, clear skies everyone. Keep looking up and keep them cameras clicking.
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