CTA 1 - Echoes of a Hidden Remnant | 400 Hours

Image processing: Maksim Zaharov (svarschik911) https://deepskyhosting.com/svarshchik911

Processing software: PixInsight, Adobe Photoshop

Imaging period: late July — mid-September 2026

The idea of imaging CTA 1 arose because, until now, there was no wide-field image of this region in which both the IFN structure and the faint background hydrogen emission were well expressed simultaneously. Our goal was to show both components in a single frame while preserving their natural contrast and large-scale structure. This approach made it possible to present the CTA 1 region in a form rarely seen in previous images of this object.

This project shows CTA 1 in an unusually deep and wide field, combining the faint structures of the supernova remnant in Hα and OIII with extensive regions of galactic dust and IFN. Rather than filling the frame with CTA 1 itself, the composition was built to emphasize the contrast between the relatively compact supernova remnant and the vast dust structures surrounding it across the entire image field.

The deep broadband data made it possible to reveal extremely faint dust on large angular scales, while the narrowband integration revealed the subtle emission structures of CTA 1. The result is a rather rare type of image in which both the supernova remnant itself and the faint dust surrounding it play a comparable visual role.

CTA 1, also known as SNR G119.5+10.2, is an ancient supernova remnant in the constellation Cepheus, located approximately 4,600 light-years from Earth. Its age is estimated at approximately 10,000–14,000 years. Its expanding shell is particularly prominent in the radio range, while extremely faint optical shock fronts can be observed primarily in the Hα and OIII lines. At the center of CTA 1 is PSR J0007+7303 — a neutron star completing one rotation in approximately 316 milliseconds. This object is particularly notable for being the first pulsar discovered through its gamma-ray pulsations rather than through previously detected radio pulsations. The extensive dust structures visible throughout the image, although on the same line of sight, are not necessarily physically associated with the supernova remnant itself.

Exposure

Hα — 230 h

OIII — 110 h

RGB — 51 h

L — 9 h

Total integration — 400 hours

Participants

1. Dmitry — 65 h

35 h Hα + 30 h OIII

Takahashi FSQ-106 / QHY600

2. Evgeniy Morozov — 55 h

55 h Hα

William Optics RedCat 71/350 / ZWO ASI2600MM Air

3. Poppy8micro — 39 h https://deepskyhosting.com/id1803

26 h Hα + 13 h OIII

Askar 71F + 0.75× reducer / ZWO ASI2600MM Pro

4. Lex Kasatkin — 35 h

21 h Hα + 5 h OIII + 9 h L

Askar SQA60 / ZWO ASI294MM Pro

5. Andrew Batov (KonFuz) — 29 h

23 h Hα + 6 h OIII

Askar 106SQA / SkyEye62AM

6. Alexey (lxkor) — 26 h https://deepskyhosting.com/lxkor

13 h Hα + 13 h OIII

Askar SQA55 / ToupTek ATR2600M

7. Maria-Mria — 24 h https://deepskyhosting.com/id1528

21 h OIII + 3 h Hα

Askar SQA55 / ZWO ASI2600MM Pro

8. Dmitry — 24 h

15 h Hα + 9 h OIII

Askar SQA85 / ZWO ASI2600MM Pro

9. Cho YongJun — 23 h

13 h Hα + 10 h OIII

Askar FRA400 / ZWO ASI2600MM Pro

10. Alena Kiseleva (BeautyS89)— 23 h https://deepskyhosting.com/BeautyS89

23 h RGB

Askar SQA55 / ZWO ASI2600MC Pro

11. Sergay Nazarov — 19 h

16 h Hα + 3 h OIII

Celestron C11 + HyperStar, ~580 mm / camera on IMX6200

12. Pingulator — 13 h

13 h RGB

Askar SQA55 / ZWO ASI2600MC

13. Yu Mar — 10 h

10 h Hα

Askar SQA55 / ZWO ASI2600MM Pro

14. Timofey Prozorov — 9 h

9 h RGB

Askar SQA55 / Player One Poseidon-C Pro (IMX571)

15. Anastasii — 4 h https://deepskyhosting.com/Anastasii

4 h RGB

Askar SQA55 / ZWO ASI294MC Pro

16. Serge — 2 h https://deepskyhosting.com/id2287

2 h RGB

Askar SQA85 / ZWO ASI2600MC

This image is the result of the collaborative work of astrophotographers imaging with different optical systems and collecting data over nearly two months. A total integration of 400 hours made it possible to simultaneously show the extremely faint emission structures of CTA 1 and the large-scale galactic dust surrounding the object in the image field.

Many thanks to everyone who took part in this collaborative project and contributed their time and data. Each participant's contribution became an important part of the final image, and without the joint work of all participants this project would have been impossible.